The EZ Lock Interface Bracket part# for this wheelchair is:

BKT-M11
This EZ Lock Interface Bracket was designed for the Quickie Freestyle M11 or Guardian Aspire M11 power wheelchairs manufactured by Sunrise Medical.
IMPORTANT:
The vehicle's lap & shoulder belts must be utilized in order to provide a complete occupant restraint.
All EZ Lock DRIVER applications require installation of the stabilizer kit (included with this interface bracket kit).