Certainly the first 'snail' i've seen for a GBB. Interesting stuff.
Actually, Tanaka make (or used to make) one for their Luger but it's rare to see one.
When I want your opinion - I'll tell you what it is!
With the holsters for both the the luger and the snailmag you'd look properly cowboyed up! 
But agreed,a pain in the but to carry around..Nevertheless a interesting item to add to the collection..
ironfoot Airsoft actually have a few of the 50rnd gas snail mags in for the Luger, though at £96.99 Each... I'll just stick to the regular mags thanks x.x
i have to say it.....WHY OH WHY ARE THEY MAKING STUFF LIKE THIS THAT WAS VERTUALLY NEVER SEEN WHEN WE ARE CRYING OUT FOR DECENT AFFORDABLE ENFIELDS AND MAUSERS!!!!!!!!
rant over.
( they are going to re-tool and set up costing loads, to sell 10.........if they are lucky) ffs.