This is a brake caliper rebuild kit made by AP (Liberty Vehicle Technologies) which was the original equipment manufacturer for MGA, MGB and TR8. By using an OEM kit you know the seals are a perfect fit and the metal retaining ring is the correct size. Many time the aftermarket kits the sizing varies which make it impossible to get a good seal. If you are taking the time to rebuild your OE calipers, use an OE Kit. The kit includes all the seals and instructions to rebuild ONE caliper. ***Two kits will be needed per car***. A great quality kit made in the UK.