Thanks Smeagol, the details of the device can be found in this brochure:-
http://www.donutsafetysystems.com/pdf/Donut%202007.pdf
Looks like a canny bit of kit. One thing that would concern me though is fire resistance, particularly of the tape, and particularly the bit of the tape that is secured to the oil rig. Do you know if it is capable of retaining its strength in the sort of high temperatures that Piper Alpha sustained? Given that it is designed to keep personnel suspended above the sea so that they may be easily sighted, remain reasonably warm and dry, and can be picked off by rescue craft, such qualities would appear essential, yet the blurb merely speaks of the 'high strength' of the tape, and the 'extreme heat' that it mentions is merely that of the Middle East, Far East and Australian environments.
Strange that such vital properties of an escape system from such potentially inflammable locations are not mentioned. A bit like selling Fire Doors with no mention of the duration of the fire resistance that they provide...
Danny, perhaps as you have just done the RAF Fire Officers Course you might have a view? I have a suspicion that it might well be down to our old friends from the "Tripped or fallen at work? Then dial 0870****** and we will get you rewarded".
If you make no claims for your product then presumably you cannot be sued for not meeting them, which is almost as pointless as the Victorians' advertising copy that knew limits in claiming miraculous properties for their medicinal compounds.