The idea is that it allows you to pedal your chain back on again without having to stop
Using MRP’s abbreviation decoder, I worked out the AMG V2 is the second generation all mount guide designed for 1x drivetrains.
It’s uses a new, smaller and lighter upper guide, and features an integrated bash plate. It will fit both ISCG drillings and is available in 26-32t and 32-38t sizing.
Like a lot of new chain devices designed for single-rings, it provides passive retention — meaning no element of the guide makes contact with the chain under normal use. The idea is that it doesn’t really stop the chain falling off, but rather allows you to pedal it back on again without having to stop.
The AMG V2 is mounted at the top of the chain, which is engaged on a couple of teeth and this means the chain will never fully disengage from the ring. Combined with a narrow/wide ring, the AMG V2 offers belt-and-braces security, and is useful if you’re racing enduro, or just don’t want to get your hands dirty.
I’m not convinced you need a lower bash guard, even for racing, simply because the chain is constantly on the teeth with a single-ring, so there’s less chance of dental damage during a rock roll or log hop. Ditching the lower bash, and opting for just the upper retention — available as the 1x V2 — will save £40.
The chain on my Giant Reign has remained secure during a few months of riding. It doesn’t touch the ring, so is totally silent, and with a smooth surface on the bash, mud build up hasn’t been an issue.