This is the new Factory RC AE B5m Carbon Fiber Shorty Brace with adjustable battery stop blocks. This brace replaces the stock plastic battery retainer bracket and allows you to use the adjustable battery stop instead of foam blocks. This brace allows you to run the battery shifted forward or rearward. Simply install the battery stop on either side, and adjust to your packs length to remove any slack. Remove a battery stop to allow full rearward or full forward positioning in the car. Fitment is snug and prevents the battery from shifting. This brace is designed to be narrow allowing for additional chassis flex in the car. Battery brace is made from 3mm Carbon Fiber and your choice of Heavy Duty Carbon Steel screws or Titanium Screws.