Dont buy a little one, I had one and threw it over, that was the last time I saw it. The force of the current on the line overcame the floats floatiness.
Saw this one on spearboard.
Also spearfishing specialties sells one that I saw being used in palm beach(bigtime current) so you know it's good. You make a loop every 20 ft and rig it in advace for 40, 60, 80 ft whatever. A 3lb dive weight was used as the anchor that way it doesnt hang up on anything.
The white and pink ones are easiest to make.
Or make your own with 2 pelaj floats or big float like above, glued together and a recess cut into it to wrap the line around.