Extension panels secure onto Model No. MC550 to allow the use of a wheel chock like Model No. RPS2KD. Durable all steel construction prevents panels failing. Metal bars slide into welded steel tubes and are secured with 4 hooked clevis pins.Extension panels secure onto Model No. MC550 to allow the use of a wheel chock like Model No. RPS2KD.Durable all steel construction prevents panels failing.Metal bars slide into welded steel tubes and are secured with 4 hooked clevis pins.Model No. MC550SASpecifications:Model No MC550SABrand: SealeyAdditional Width: 340mmPanel length: 700mmCompatiablity: MC550