These little suckers are sure to get your lips warm and tingly.... Made from 4 different materials they are specifically for the top caps with sticking up steeples. They only measure about 3.5mm from 510 receptacle ....This way it turns that whole section into the tip!! Keeping the appearance of lowest possible cap height!!! Illusions...... aren't they cool?!?! Not meant for flat caps unless you wanna DROP it like its HOT!!!