Maybe I'm looking at the wrong thing... the website says it is a cover only (no core) that i can use to beef up my 3/8" line so it doesn't slip in the rope clutch. My rope clutch can handle 3/8" as the smallest size, so it does slip occasionally when tensioned up (it's old and probably needs a new cam).

The line on there currently is 3/8" (possibly warpspeed II) with the extra cover where it grips the spinlock. Obviously serves dual purpose: won't slip in rope clutch and tells me when I'm at full hoist.

I have 3/8" Sta-Set X but need to beef up the clutch area with additional cover material...

I picked up a couple of feet of 7/16" cored and 1/2" cored line and will strip the cover off this to see if I can fit it over the 3/8" line and lock stitch/whip.

How do you determine what model a Spinlock is? I can't see where the model # or type is printed/listed on it, but it looks like an earlier generation than the ones in the store now.. They're probably 10 years old...