With a larger pen body than our standard pens, HD pens are build for maximum durability. They have heavier connector posts and heavier tips. HD pens require a higher heat setting than most standard pens and are best used with a heavy duty (HD) cord. These pens operate up to 5 times cooler than Razertip’s previous pens. For high heat users, the new pen bodies will cool off much quicker than ever before. You won’t find a more comfortable pen anywhere!