By angular is meant the strutted brake arm, which is also visible from the underside of the vehicle. Some vehicle series (e.g. V50 / ET3) were initially equipped with the older (round) type, later (~1978) they were converted to the square type shown here.
TIP: If the vehicle has a square cutout for the brake pedal arm in the floor plate, the pedal shown here will fit. If a smallframe (V50, ET3 etc.) has a round hole, it is better to use the older pedal type (7900107) to avoid damage to the paintwork during assembly.
NOTE: PX old models (up to year 1984) use the square pedal type, but still have a round cutout in the chassis. Here simply use the round seal/stop rubber.