Halcyon's always on the lookout for ways to make diving easier for divers who must wear thick gloves while underwater.
Fumbling with a spool while wearing dry gloves can be a serious hassle. While the "traditional" approach would be to just enlarge the spindle hole size, the staff at Halcyon had a different idea: in addition to a larger center hole, add a flanged edge around the spindle, which allows the spool's double-ender to double as a handle to greatly simplify line retrieval.