This is Railscale33d's printed version of the popular NEM pocket seen on many N scale/N Gauge models. It functions the exact same way, and will fit both Rapido and Dapol Knuckle Couplings. This NEM pocket is currently used on our N Gauge OTA wagons and has so far showed no signs of not being able to keep up with the injected moulded counterparts
 
This is nothing different, just a lot cheaper 
 
If you are still unsure of its function then please see the video in the photo gallery of this product 
 
Please Note: These come printed in Grey coloured resin