a. XX-170R - non proportional. works with 2 pin toys gearbox type of servo

b. XX-162R - proportional. works with standard 3 pin servo

c. XX-184 - new non-proportional receiver board

d. XX-318R - old D12 receiver board

e. XX-339R - new D12 receiver board

f. XX-363T - D12 Remote board

g. XX-412R - new proportional receiver for B & C series RTR. Release Year 2022.

h. XX-532R - new board introduced in the new gen C54-1 RTR. Compatible with old WPL remote

i. XX-652R - used on the C14 & C24 RTR from March 2023