1. Base-Closed extensions are populare for EU market.
2A,3A with 6mm steel plate; 4A with 8mm thickness steel plate.
2. Base-opened extensions are popular for North America.
light duty for 2A,3A forks.
3. The length of extensions should not exceed 150% of the forks.
For example,the forks are 1200mm,then the Extensions should be less than 1800mm.