Airtac HPA/M4 magazine adapter for GHK G5

I’m selling a brand new, unused M4 magazine adapter for the GHK G5 as i no longer own the gun, and never even used the adapter fit it (because i never even got to the point where i reinforced the gun to make it ready to use with HPA, and moved on to other projects instead).

I’m looking for £55 for it, plus £5 for postage.