5x11x4mm rubber sealed ball bearing. Used in many Traxxas models, and common in other brands. Two per package.
Compatible with:
Traxxas Bandit
Traxxas E-Maxx
Traxxas E-Revo VXL 2.0
Traxxas Jato
Traxxas Nitro 4-Tec
Traxxas Nitro Rustler
Traxxas Nitro Slash
Traxxas Nitro Stampede
Traxxas Rally
Traxxas Revo
Traxxas Rustler
Traxxas Slash
Traxxas Slash 4x4
Traxxas Slash 4x4 Ultimate
Traxxas Stampede
Traxxas Stampede 4x4
Traxxas T-Maxx
Traxxas Telluride 4x4
Traxxas X-Maxx