The STBO side mounting brackets point outwards from the seat to allow for easy access to the chassis mounting bolts. They are identical to the PTBI but made of 5mm aluminum and powder coated. The seats can be tipped, raised and lowered. They are compatible with all versions of the B6 Screamer XL (Side Mount), B7 XL and B10 XL - which all have mounting bolts at 2 degrees. They can be run with Tillett STRO or PTRO sliders for XL width seats, though it generally recommended to not user sliders in race car applications. Fixed mount to chassis is recommended.