$re = '/<div[\s\S]*?id=\"variationsTwister[\s\S]*?<span[\s\S]*?a-dropdown-container[\s\S]*?<select[\s\S]*?<\/select>[\s\S]*?Color:<\/span>[\s\S]*?<span[\s\S]*?>([\s\S]*?)<\/span>/m';
$str = '<div id="variationsTwister" class="a-section a-spacing-mini">
<div class="a-section a-spacing-micro">
<span class="a-size-base">Size:</span>
<span class="a-size-base a-text-bold"></span>
</div>
<span class="a-dropdown-container"><select name="" autocomplete="off" data-a-native-class="olpTwisterDropdown" tabindex="-1" class="a-native-dropdown a-spacing-small olpTwisterDropdown">
<option value="/gp/offer-listing/B00NNA39IE/ref=olp_twister_all?ie=UTF8&mv_color_name=3&mv_size_name=all">
Lowest offer for each
</option>
<option value="/gp/offer-listing/B00MC3QSKO/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=0">
5 M US
</option>
<option value="/gp/offer-listing/B00MC3QU1G/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=1">
5.5 M US
</option>
<option value="/gp/offer-listing/B00MC3QX72/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=2">
6 M US
</option>
<option value="/gp/offer-listing/B00MC3QYQC/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=3">
6.5 M US
</option>
<option value="/gp/offer-listing/B00MC3R0PQ/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=4">
7 M US
</option>
<option value="/gp/offer-listing/B00MC3R23Q/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=5">
7.5 M US
</option>
<option value="/gp/offer-listing/B00MC3R3M6/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=6" selected="">
8 M US
</option>
<option value="/gp/offer-listing/B00MC3R6LO/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=7">
8.5 M US
</option>
<option value="/gp/offer-listing/B00MC3R9IY/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=8">
9 M US
</option>
<option value="/gp/offer-listing/B00MC3RBE6/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=9">
9.5 M US
</option>
<option value="/gp/offer-listing/B00MC3RCPY/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=10">
10 M US
</option>
</select><span tabindex="-1" id="olpTwisterDropdownAUI" class="a-button a-button-dropdown a-button-small a-spacing-small" style="min-width: 0.583333%;"><span class="a-button-inner"><span class="a-button-text a-declarative" data-action="a-dropdown-button" role="button" tabindex="0" aria-hidden="true"><span class="a-dropdown-prompt">
8 M US
</span></span><i class="a-icon a-icon-dropdown"></i></span></span></span>
<div class="a-section a-spacing-micro">
<span class="a-size-base">Color:</span>
<span class="a-size-base a-text-bold">Taupe</span>
</div>
<ul class="a-unordered-list a-nostyle a-button-list a-declarative a-button-toggle-group a-horizontal a-spacing-small" role="radiogroup" data-action="a-button-group">
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-normal a-button-thumbnail a-button-toggle" id="a-autoid-0"><span class="a-button-inner"><a href="/gp/offer-listing/B0002MB0DM/ref=olp_twister_child?ie=UTF8&mv_color_name=0&mv_size_name=6" class="a-button-text" role="button" id="a-autoid-0-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/41jl1EwZjHL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</a></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-normal a-button-thumbnail a-button-toggle" id="a-autoid-1"><span class="a-button-inner"><a href="/gp/offer-listing/B005BFV1DO/ref=olp_twister_child?ie=UTF8&mv_color_name=1&mv_size_name=6" class="a-button-text" role="button" id="a-autoid-1-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/41XqEgaqwtL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</a></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-normal a-button-thumbnail a-button-toggle" id="a-autoid-2"><span class="a-button-inner"><a href="/gp/offer-listing/B00MC3SFXW/ref=olp_twister_child?ie=UTF8&mv_color_name=2&mv_size_name=6" class="a-button-text" role="button" id="a-autoid-2-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/41cNhnckTFL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</a></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-selected a-button-thumbnail a-button-toggle" id="a-autoid-3"><span class="a-button-inner"><a href="/gp/offer-listing/B00MC3R3M6/ref=olp_twister_child?ie=UTF8&mv_color_name=3&mv_size_name=6" class="a-button-text" role="button" id="a-autoid-3-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/41p2f8xA8TL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</a></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-normal a-button-thumbnail a-button-toggle" id="a-autoid-4"><span class="a-button-inner"><a href="/gp/offer-listing/B011SBR9PS/ref=olp_twister_child?ie=UTF8&mv_color_name=4&mv_size_name=6" class="a-button-text" role="button" id="a-autoid-4-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/311Xw94d26L._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</a></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-normal a-button-thumbnail a-button-toggle" id="a-autoid-5"><span class="a-button-inner"><a href="/gp/offer-listing/B07FYS34S4/ref=olp_twister_child?ie=UTF8&mv_color_name=5&mv_size_name=6" class="a-button-text" role="button" id="a-autoid-5-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/41r4qvtmEkL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</a></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-normal a-button-thumbnail a-button-toggle" id="a-autoid-6"><span class="a-button-inner"><a href="/gp/offer-listing/B00MC3TVSK/ref=olp_twister_child?ie=UTF8&mv_color_name=6&mv_size_name=6" class="a-button-text" role="button" id="a-autoid-6-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/31YEDbIcNwL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</a></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-normal a-button-thumbnail a-button-toggle" id="a-autoid-7"><span class="a-button-inner"><a href="/gp/offer-listing/B016W1Z1RC/ref=olp_twister_child?ie=UTF8&mv_color_name=7&mv_size_name=6" class="a-button-text" role="button" id="a-autoid-7-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/41plM8TSFBL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</a></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-normal a-button-thumbnail a-button-toggle" id="a-autoid-8"><span class="a-button-inner"><a href="/gp/offer-listing/B0007L7WPS/ref=olp_twister_child?ie=UTF8&mv_color_name=8&mv_size_name=6" class="a-button-text" role="button" id="a-autoid-8-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/41NGM8gp7hL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</a></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-disabled a-button-thumbnail a-button-toggle" id="a-autoid-9"><span class="a-button-inner"><input disabled="disabled" class="a-button-input" type="submit" aria-labelledby="a-autoid-9-announce"><span class="a-button-text" aria-hidden="true" id="a-autoid-9-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/41WBKxWvoLL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</span></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-disabled a-button-thumbnail a-button-toggle" id="a-autoid-10"><span class="a-button-inner"><input disabled="disabled" class="a-button-input" type="submit" aria-labelledby="a-autoid-10-announce"><span class="a-button-text" aria-hidden="true" id="a-autoid-10-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/41ap6ahxMRL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</span></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-disabled a-button-thumbnail a-button-toggle" id="a-autoid-11"><span class="a-button-inner"><input disabled="disabled" class="a-button-input" type="submit" aria-labelledby="a-autoid-11-announce"><span class="a-button-text" aria-hidden="true" id="a-autoid-11-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/41QD5K54hPL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</span></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-disabled a-button-thumbnail a-button-toggle" id="a-autoid-12"><span class="a-button-inner"><input disabled="disabled" class="a-button-input" type="submit" aria-labelledby="a-autoid-12-announce"><span class="a-button-text" aria-hidden="true" id="a-autoid-12-announce">
<img alt="" src="https://images-na.ssl-images-amazon.com/images/I/31qtQ78OWiL._SX35_SY35_CR,0,0,35,35_.jpg" height="35" width="35">
</span></span></span>
</span></li>
<li class="a-spacing-mini"><span class="a-list-item">
<span class="a-button a-button-normal a-button-toggle" id="a-autoid-13"><span class="a-button-inner"><a href="/gp/offer-listing/B00NNA39IE/ref=olp_twister_all?ie=UTF8&mv_color_name=all&mv_size_name=6" class="a-button-text" role="button" id="a-autoid-13-announce">
Lowest offer for each
</a></span></span>
</span></li>
</ul>
</div>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php