hahahaha, those shockchords suck so bad. Someone gave me a speargun once with one of those things on, and let me tell you, don't waste your money. As soon as you pull the trigger your accuracy is impaired (due to the shockchord tugging on your spear) and as soon as you reach the end of the chord it becomes a tangled mess. Bad idea.
however, they make great speargun leashes. I put a key ring on my handle, hooked my extra shockchord onto it, then a loop of rubber on the other end. Its great if you only need another ten feet or so to reach the surface but don't want to ditch your gun.
I think my favorite toy is my
JBL sliptip. I replaced the retarded steel cable with braided dacron that sits int the line hole with a knot keeping it from sliding off. its very sleek and keeps your fish on.