This is a custom "L-Brace", which is intended for use on a Kyosho Lazer ZX 1/10 4WD buggy. This "L-Brace" is fully compatible with the original parts from Kyosho (LA-31) as well as the custom "Deck Mount" of the "Kyosho Lazer ZX - Belt Tensioner + Deck Mount Kit" (available in this shop).
The "L-Brace" features an additional mounting point on the deck mount for improved rigidity.