The only Slik blocks I have seen are of the 2k length. Evo bolt length is shorter, where the back block is milled from a part of the receiver (I think) and the back block is flat at the back, with part of the block extending into the body. Eclipse cockers are all evo length, as are some AKA bodies and others.
Mine's black, and I have only seen other black ones. There may be chrome available, I don't know. It is ugly as hell on my cocker, but the performance can't be argued with. I get checked for bounce all the time, but I have only had one ref ever manage to get it bouncing. It is the fastest eBladed cocker I have ever seen, and low reciprocating weight is a big part of my recipe. I think I saved something like 38 grams changing to the Slik.
Sorry to go off topic.