Wow! That's one massive bike lock! The SAF Lock – the first angle grinder-proof bike lock, according to US brand Altor – is currently looking for funding on Indiegogo.

The 14mm hardened steel core shackle is surrounded by a thick aluminium shell to give a total diameter of 75mm. The idea is that an angle grinder with a 5in disc can't cut deep enough to get to the steel inside.

"The combination of the material and the inner shape of the SAF Tech Shell makes for a terrible cutting experience which wears through angle grinder discs and batteries," says Altor.

The SAF lock weighs about 6.25kg (13.7lb) so it's the sort of thing designed to be left permanently in place in your garage or at your office, rather than carted around in a backpack.

"While all bike locks on the market that we've tested were cut in under 45 seconds, the SAF Lock outlasted every portable angle grinder," says Altor.

The Indiegogo campaign runs for another nine days but it has currently reached only 9% of its £51,000 funding goal. Super early bird offers are still available where you're in line to receive a SAF Lock for £164 in March 2020 – but only if the funding target is met (and all other Indiegogo rules apply, of course).

Visit the Altor SAF Lock Indidgogo page.