The Harbor Freight chock is the same one as the Northern Tool one...http://www.harborfreight.com/motorcy...ock-69026.html

I wanted mine removable so I took the chock off of the base and mounted it to the trailer with these...http://www.homedepot.com/p/Cargo-Bos...ct_description

Here's a different view of them....http://www.compacc.com/images/product/300/17128_1.jpg

I used regular bolts instead of the eye-bolts that they came with, and put a large washer underneath to spread the load out. You can also use them as they are intended for the tie down points if you aren't gonna run e-track...