JSFiddle - React, Tailwind, and code Playground

HTML

<div id="cupSelect" class="control-group">
    <label class="control-label" for="cup-select">Select your Tumbler size you are interested in customizing:</label>
    <div class="controls">
        <label class="radio-inline" for="cup-select-0">
            <input name="product" id="cup-select-0" value="20oz" checked="checked" type="radio" class="radio_item">
            <img src="/ImageStore/ClientSite/7798/Resources/Contact/20oz-blank.png" alt="20oz Tumbler">
            <p class="text-center size-12">20 oz</p>
        </label>
        <label class="radio-inline" for="cup-select-1">
            <input name="product" id="cup-select-1" value="30oz" type="radio" class="radio_item">
            <img src="/ImageStore/ClientSite/7798/Resources/Contact/30oz-blank.png" alt="30oz Tumbler">
            <p class="text-center size-12">30 oz</p>
        </label>
        <label class="radio-inline" for="cup-select-2">
            <input name="product" id="cup-select-2" value="Lowball" type="radio" class="radio_item">
            <img src="/ImageStore/ClientSite/7798/Resources/Contact/lowball-blank.png" alt="Lowball">
            <p class="text-center size-12">Lowball</p>
        </label>
        <label class="radio-inline" for="cup-select-3">
            <input name="product" id="cup-select-3" value="Colster" type="radio" class="radio_item">
            <img src="/ImageStore/ClientSite/7798/Resources/Contact/colster-blank.png" alt="Colster / Can">
            <p class="text-center size-12">Colster</p>
        </label>
        <label class="radio-inline" for="cup-select-4">
            <input name="product" id="cup-select-4" value="18oz" type="radio" class="radio_item">
            <img src="/ImageStore/ClientSite/7798/Resources/Contact/18oz-blank.png" alt="18oz Bottle">
            <p class="text-center size-12">18 oz</p>
        </label>
        <label class="radio-inline" for="cup-select-5">
            <input name="product" id="cup-select-5" value="36oz" type="radio"...

JavaScript

var products = document.getElementsByName('product');
for (var i = products.length; i--;) {
    products[i].addEventListener("click", function() {
	    var cup = this.value;
		document.getElementById('yourSelection').value = cup;
        document.getElementById("cupDesc").style.display = "block";
		document.getElementById("cupSelect").style.display = "none";
    });
}