The trouble is, I wouldn't give two old pence for any of them. The inventions that would really enhance the diving experience haven't been invented yet. Take the TWAT, for instance - the Tropical Water Adjustment Thermostat. This will control a network of electrical elements, buried in shallow trenches running from Cape Wrath to Land's End. It has always amazed me that the civilisation that put a man on the moon can't come up with something a little more jolly to hang on our weightbelts.
Lead is so awfully grey and heavy, darlings.
Whereas polystyrene is so cheery and frivolous and gay. On a different note, I've never recovered from the disappointment of learning that Jet Fins were nothing of the sort. I complained to the Advertising Standards Authority. It would be diving's answer to the motorised golf buggy. The sport would be opened instantly to septuagenarians with heart conditions.