Axial AXI332005 2-Speed Set RBX10 Cen Racing Parts The product page also mentions

The product page also mentions an 8

This is a genuine HPI Racing 4mm motor plate in gray for the Savage XL Flux

Part number LA370

Fitment is the widest of the MP9 hub parts

Axial AXI332005 2-Speed Set RBX10 Cen Racing Parts The product page also mentionsAxial AXI332005 2 Speed Set RBX10 This genuine Axial 2 speed set is a replacement or upgrade option for the RBX10, giving drivers a low gear for technical crawling and a high gear for faster runs. Precision manufactured to Axial's specifications, it's built to hold up under the stress of shifting between gear ranges. Genuine Axial replacement option part Fits the RBX10 2 speed gear set for dual range driving Durable construction for repeated use