Do not be mad that it does not look as a usual deal. Please let me explain.
This thing on the listing is not a typical compensator. It reduces perceived noise on the shooter side by 3 decibels as it directs noise forward. It is not much but noticeable and it is not a suppressor. You do not need a stamp to buy it.
Recently I purchased a similar one from Kaw Valley and paid 39.95$ plus shipping.
Then I found this one that seems to look kind of better and costs a half of the price with a free shipping.
Do what you want to do but it felt fare to share. If admins feels it is not a deal please delete this post and pardon me.