This is a toy replica of the gun used by superhero Britt Reid (Seth Rogen) as featured in the Michel Gondry directed 2011 movie The Green Hornet
It’s made of plastic and is really designed for cosplay.
Manufactured by Rubie’s Costume Co and is a much more realistic reproduction of the gun than this Green Hornet Gun toy previously released by Rubies.
Get it at the following vendors (prices vary):