Professional scalloping line, made out of 10mm rope.
Top portion is leaded rope to keep it clear of the suface, floating rope on the lower section to help keep it clear of the reef. At a ratio that works.
Spliced at the top to tie your floats to
Tucked at the sack end to provide extra rigidity and allow for spear attahement.
Finished off with a locking S/S Carabiner to allow for quick sack attachement
Add a loop for a hang tank at any depth for £6