In the early days of cave diving, reels were not available to buy off the shelf. Divers used anything they could, including empty electrical wire spools. When exploring, divers would pay out the line and if they didn't empty the spool it would be left in the cave for the next dive. The finger spool is most often used as a gap reel or for short distance exploration. Small and low-profile, a spool fits nicely out of the way in a pocket or clipped-off to a D-ring. The holes in the side allow for clipping in a double-ended snap anywhere along the perimeter of the spool to keep the line-tight when not in use.
The XS Scuba Flared 304 Stainless Steel Spools with anodized surface have flared edges which are easy to grip and keep fingers out of the way. Spools come with #24 orange line, 8 strand with a breaking strength of 168 lbs.