Front Hub

Dual Thread Hub: This could imply that the hub has threads (internal or external) designed to fit different types of threading patterns for attaching a freewheel or a cassette. The hub might have threads compatible with both freewheels (which screw onto the hub directly) and cassettes (which slide onto a cassette body).

40 Spokes Hole: This indicates the number of spoke holes present in the hub flange where spokes are inserted and secured. A wheel with 40 spokes provides greater strength and stability compared to wheels with fewer spokes, making it potentially suitable for applications that require more durability,