Made for tent greenhouse. ITs designed to hook onto a 24mm in diameter bar and attatch an 13mm inner idameter plastic tube (PVC PIPE) as extra support for the tent like greenhouse roof so water dont build up.

The one with a spool was designed to hold plants with a string and pull with a counterweight that supports the plant as it grows.
24mm to 13mm hook needs to be scaled up to 1000%

100% infill
nylon would be the prefered material