Hot Racing 43mm Internal Spring Air Shock. These optional shocks are intended for the Losi 1/24 Micro Crawler and the Trail Trekker. 

Features:
CNC machined aluminum shock bodies
Stainless steel shocks shafts
Air damping
Internal springs, including three spring rate options
Specifications:
Extended Center to Center Length: 43mm
Compressed Center to Center Length: 33.5mm
Overall Length: 48.7mm
Body Diameter: 5mm
Shaft Diameter: 2mm
 
Includes:
(4) assembled aluminum shocks
(4) shock end pivot balls
(3) spring sets (one set factory installed in shocks)
Installation hardware kit (M2.5)