These are 5mm Nylon Locknuts by Traxxas.
FEATURES:
Blue anodized aluminum construction.
Nylon inserts.
INCLUDES: Four 5mm locknuts.
SPECS: Thickness: 4.95mm (.195")
Fits:
1/10 E-Revo / E-Revo Brushless / Nitro Jato 3.3 / Nitro Sport / Nitro Stampede / Revo / T-Maxx / Slayer Pro 4x4 / Nitro Rustler / T-Maxx Classic