If you were ever curious whether the 400lb and 300lb rated Speardiver mono line actually lives up to its name, I made this video. The machine measures the increasing load in pounds, and stops automatically when the line breaks. You can see how low stretch the mono is, this is crucial to maintain a high breaking strength when using crimps.
Speardiver 400lb mono speargun shooting line test - YouTube
Speardiver mono shooting line is available from www.FreediveStore.com. 400lb and 300lb 100 yard coils, in black, blue, red and hi-vis yellow/green.