This knife is a Tony Bose pattern Backpocket by John Lloyd. The covers are very hard  moose bone from the top of the animal's skull called the pedicel. It is 4-5/8" closed ,blade is 3-5/8" with 3-3/8" of cutting edge .Opens to 8-1/8" OAL. Blade & spring are CPM-154 stainless . Liners ,pins ,inlaid shield and bolster are stainless . Smooth 5+ action,I can pinch it on a certain spot of the blade right at the plunge spot on the blade's swedge. Feels great in the hand ,nice full size slipjoint folder by John Lloyd
​$550.