The stones are triangular flat sides for plain edged blade and the corner for serrated edges, a furrow runs down the middle of each flat side for sharpening pointed items.4 stones are included, 2 medium-grit, brown, high alumina ceramic stones (178mm x 13mm) for the more serious grinding and 2 fine white high alumina ceramic stones of the same size for getting the final razor edge, these stones then slot into shaped whole on the base.The lid re-connects with the base for you to hold for stability and 2 brass rods can be inserted to protect the hand.

The stones can be set accurately at 30 (15 degrees each side) 40 (20 degrees each side) you can also turn the base over and place the stones into the back so it can be used as a benchstone.

The ceramics are similar to that of glass and can shatter if they are dropped, the case on the other hand is constructed from a durable ABS plastic.

Your knife considered by most the most important tool as a survivalist needs to remain sharp, for this the Spyderco Triangle Sharpmaker is ideal and will allow you to get the perfect edge on all your blades.