With years of BDSM experience these collars were made to solve several problems typical collars have. One of the biggest additions is hook and loop fastener to make applying the collar easier and to prevent the splitting effect during rough play. Splitting refers to the strap overlap in the buckle area and with heavy movement the ends can drift vertically creating the split. Application wise it helps a lot to get the starting desired tightness and then can take your time tightening the buckle without worrying about the collar falling off. There is just enough hook and loop to tackle these problems while staying out of sight when the collar is actually on, thus keeping a sexy classic look.
Garment leather is used to make the liner which acts as padding for the interior and edges. There is just enough to make them comfortable without over doing it on padding which tends to result in a bulky look. The liner also makes it so there is no metal directly touching the skin, thus much less maintenance or allergy concerns.

For other small details all edges are beveled / smoothed and I make sure to include keepers so the slack can be properly secured and everything looks sleek and proper.
Approx 2.125" wide with lining, with main strap using .75" buckle and D-rings, 2"ish of main size adjustment zone. Main D-ring is screw on style so ring can be swapped or taken out. Be sure and check out all the ring options!

Current offerings color / hardware wise:
Black leather / silver hardware (locking buckle or regular buckle)
Black leather / brass hardware (only regular buckle)
Black leather / antiqued brass hardware (only regular buckle)
*NOTE: As a work around, regular roller buckles are also lockable using small locks.

Made to order so be sure and give neck size and any hardware notes!
To clarify the listing is for 1 collar with an O-ring and no other items are included. Last image shows O-rings with inner diameter approximations.