Net Light
A matrix net, the century one or maybe even a MCF one. All lovely nets, well over a ton and yet no room for an isotope in the block. This friendly barrel of PTFE takes an isotope, then attachs to the mesh via two cable ties, located in the indents of the PTFE.

Simple, very effective and a lovely subtle glow, not a fish scaring blast of light. If you own a net with an isotope facility, don’t feel left out and be laughed at for being poor, attach it to the net cord so that it welcomes them aboard.