Looks just like this one:
http://www.google.com/products/catalog?client=firefox-a&rls=org.mozilla:en-US:official&channel=s&hl=en&q=valve+spring+compressor&um=1&ie=UTF-8&cid=10800365620945000690&ei=raHhTNqpFMKblgfk8ZTiCA&sa=X&oi=product_catalog_result&ct=image&resnum=3&ved=0CC8Q8gIwAg#
If they fixed the spawn issues in HC Deathmatch, the algorithms for shot accuracy, and letting you hear the other team's footsteps (unless running Ninja), it'd be a great multiplayer game.