<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
.diametr_form label{
display: table-row;
}
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script>
$(".d100").change(function() { $('.prom_vents~#product[class~="100"]').hide(500);
if(this.checked) { $('.prom_vents~#product[class~="100"]').show("slow");
} else { $('.prom_vents~#product[class~="100"]').hide(500); }
</script>
</head>
<body>
<form method="post" action="" class="diametr_form"><label></label>
<label><input type="checkbox" name="diametr" value=".d100" class="d100" />100 мм</label>
<label><input type="checkbox" name="diametr" value=".d125" class="d125" />125 мм</label>
<label><input type="checkbox" name="diametr" value=".d150" class="d150" />150 мм</label>
</form>
$result = mysql_query(" SELECT * FROM `product` WHERE `brand`='Вентс' ");
$row = mysql_fetch_assoc($result);
mysql_close();
while($row = mysql_fetch_assoc($result)){
?>
<div id="product" class="<?= $row['model']; ?>" >
<?php
}
</body>
</html>