I just had the chance to measure two Salvimar pneumatic speargun with a builder's rule which is way easier than using a retractable tape which flops around while you are trying to lock the tape in position. To my surprise the Predathor Vuoto 100 measured 107 cm from muzzle tip to rear valve cap and the Vintair Vuoto (Vuoto Air) 85 measured 92 cm, so that is 7 cm extra in both cases above the nominal length. A Salvimar Vintair 35 single power measures out at 42.3 cm, so again there is that 7 cm difference.

A Mares Cyrano 1.3 blue handle 90 model measures out at 90.7 cm which is more like it, and a Miniministen 2001 model (classed as a 42) measures out at 42.4 cm.

A Cressi Saetta 88 Quasimodo measured from muzzle tip to rear valve cap is 91 cm, so that is only 3 cm different. I am surprised Cressi did not call it a 90, but maybe the marketing people thought “88” sounded better. I don't have one to measure, but it would be interesting to see what the length is for the Predathor Dark Side 99.9!