Raybestos has been making brake pads for over 100 years. They have proven themselves as a top brake pad manufacturer for both street and racing brake pads. Their street pads have been readily available for years,and now so are their race pads. Raybestos ST38
"B" slightly lower mu than ST-42. Wear still not as good as ST41. Good performance over broad temperature range with minimal rotor wear.Successful in a broad range of racing series. Use in dirt where you want less bite than ST-41/ST-43. Raybestos ST41
"A" the best high energy input racing material available. Extremely successful in all the top three NASCAR series Raced by the 2002 NASCAR Champion Tony Stewart. Maintains high mu level at extremely high temperatures without sacrificing good wear - both pad and rotor. Needs some heat to work well. Raybestos ST42
"J" lower mu than ST-41 and ST-43. Extremely stable average and in stop output over a wide temperature range. Has been very successful when used on the rear brakes in conjunction with the ST41 on the front. Best high-temperature wear of all their materials. Raybestos ST43
Friction level and wear rate between ST-41 and ST-42. Stability is not quite as good as 42 but better than 41. Excellent open wheel formula. Raybestos ST44
High friction material, slightly less aggressive than ST-41Raybestos ST45
Lower friction level than the ST-47. Could be used as a great rear to compliment the ST-47 compound.Raybestos ST47
Has the highest friction and torque available to date. It has been engineered for long-lasting extreme heat situations and maximum rotor life. If you are looking for the most advanced-performing road race brake pad, that will simply out perform all the rest, this is it.