Tow floats are useful bits of kit for a number of reasons. In swimrun terms they are great for open water training, and for some (not many) of the solo/more remote swimruns they are a mandatory piece of safety kit. That said they are not a requirement for most swimruns.
SEESWIM have produced a tow float with a large water-tight central compartment, with 2 inflatable chambers either side. The chambers are quick to inflate and deflate. It comes with 2 robust staps for carrying and a waistband. The construction seems strong and demonstrates thoughtful design.
I wanted to test how it perfomed in an "extreme" transition, hence the jetty jump video.
The tow float is attached to the waist belt by a small karabiner. This karabiner is perfectly fit for pupose for normal swimming, however if you anticipate more extreme transitions, or strong surf, I'd recommend fitting a stronger karabiner as the one supplied snapped on entering the water.