One of the best bits of kit at feck all cost, couldn’t be easier to fit and makes long distances that bit less tiresome. Bought mine from Norms delivered in 2 days
Couldn't get on with them myself, it was never in the right place on the twistgrip. As a potential alternative, have a look at Jaws throttle locks (quick search on here under Vendors of innovation). Bit more expensive but a top bit of kit that may or may not suit your needs.