Same size as:

Volcano XP4 Suspension Lower Arm (XP003) – Original spare part for the Volcano XP4

You can see which battery pack Traxxas recommends for your vehicle here:

F949-5 Landings-hjul - reservedel til F949 fjernstyret fly

Batteri AAA (4 stk.) Hammer Same size as:GP Super Alkaline 4 pcs. AAA alkaline batteries with high performance, perfect for your radio transmitter! These batteries strike a great balance between high output and performance. You'll get the best performance in your RC control by using alkaline batteries instead of rechargeables. Alkaline batteries offer higher output (1. 5V vs. 1. 2V) and maintain power longer.