The Portal gun replica is a gorgeous piece of kit. There have been imitations over the years, but this one has been commissioned by Valve. It looks the part.
Based on the Aperture Science device from the game Portal, it's life-sized. It can be held as a prop to complete a costume, or it can be displayed in pride of place as a collectors' piece.
LED lights are triggered at the pressing of a button and the operating of a thumb slide.
The Portal device replica does everything but actually open up portals. It will make it look like it did though. Lights appear! Just don't attempt to leap into the center of them. The sounds are authentic too.
A warning is attached not to peer into nor touch the operational end of the device. I like to think it's because your fingers or eyeballs will appear in a separate part of the room. But it's actually a health and safety thing.
The customizable element comes from blue and yellow magnetic strips, plus Aperture Science stickers. These can be arranged on your handheld Portal device in whichever manner creativity guides you.