We strongly recommend the X-Ring for most purposes:- Here is some info towards help you selecting your chain:- 

Compared with Normal O-Ring, X Ring has:- 

• Half the Power Loss  
• 1.5 to 2 Times Longer Wear Resistance

D.I.D’s PATENTED X-Ring construction reduces friction by twisting between the side plates instead of being squashed. Normal O-Rings and other makers’ modified O-Rings have squashed points that increase friction. The twisting action of the X-Ring disperses the pressure and minimizes power loss. X-Ring is a U.S.A. Registered Trademark of D.I.D; Daido Kogyo Co. Ltd. Japan

The X-Ring’s four contact points greatly increase its sealing performance. This keeps the dirt out and the lubrication in much better than any other O-Ring. X-Rings have the greatest wear resistance of any other type of O-Ring or Non-O-Ring chain.

Fitment and compatibility:

Chains
Chains or Sprockets
DID Chains
Gas Gas EC 350F (21-23)
Kawasaki
Kawasaki KX 250 (2011-2020)
Kawasaki KX 250 (2021-)
Kawasaki MX
Kawasaki SX 250 (21 onwards)
KTM 250 SX-F (2021 Onwards)
KTM 390 Adventure (20 onwards -)
KTM 450 SX-F (2021 Onwards)
KTM Duke 790 (2018 onwards)
Natural Steel
PowerSports Chains
Suzuki GW250 Inazuma (2014-)