​​​​21mm Nut 

12mm Axle 

Product Features
Thread: M12 x 1.5 Thread

This is the most common used nut and washer setup on 1000w motors

Dragon GT GTR etc

Includes: 1 Flat Washer + 1 Locate Washer

Material: Hardened Steel

Suits: Electric Scooters & High Performance Model

Common Electric Scooter Models That Often Use M12×1.5 Axle Hardware
Xiaomi / Segway / Ninebot Variants
Segway Ninebot MAX G30

Xiaomi Mi Electric Scooter Pro 2

Xiaomi M365 / M365 Pro

Ninebot ES2 / ES4 (older, but similar components)

These often use M12 nuts on rear and front wheel axles, though washers vary.

Apollo Scooters
Apollo Explore

Apollo Phantom

Apollo Pro

Apollo scooters generally use larger 10" wheel axles that accept M12 hardware.

Kaabo / Wolf Warrior / Mantis
These premium scooters almost always use M12 axle nuts:

Kaabo Wolf Warrior 11

Kaabo Mantis Pro

Kaabo Skywalker 10

Kaabo Electric Warrior

These models have 10" wheels where M12 hardware is standard.

Zero / Dualtron / Speedway / Fluidfare
Many performance scooters also use M12 sizes, but some may use M14 instead — so check:

Zero 10X

Dualtron Thunder / Mini

Speedway 5 / 4 Pro

Fluidfare Apollo (performance trims)

If a scooter uses 10" pneumatic tires, M12 is very common.