Is there such a thing. I haven’t got a narrow wide chainring and imam wandering if I can put a chain device on to my bike to keep the chain on. It’s an xtr trail crankset x2 and an xo front mech. Any suggestions? Thanks

I use a stinger on my Five with a double setup. Works great.
http://www.blackspire.com/qs/product/83/5947/263221/0/0

Got the e13 on my tallboy, works a treat

Composite, so that’ll work with a dual chainring crankset? I’ve always assumed something like that would only sit a single ring setup. Thanks

An alternative would be an MRP 2x, which has twin jockey wheels and an integrated bash guard. Lot more than the Blackspire, so it depends how much you want to spend.
http://www.mountainracingproducts.com/mrp/2x/

One of these highly recommended.

http://www.chainreactioncycles.com/blackspire-twinty-2x-chainguide-black/rp-prod81182

No moving parts, chain slides over a plastic runner. I had bad experiences with the roller type device, had to strip the roller down and regrease the bearing on a monthly basis due to the cr#p getting in. The twinty guide is fit and forget, just a new plastic runner (£17) after about 12 months.