There are 5 different lengths of butt extension 65mm (2.6"), 96 mm (3.8"), 116mm (4.6"), 136mm (5.4"), and 156mm (6.1")

Leshiy 2 with adjustable regulator (E.A.R. or Apex):

• Butt Extension from factory: 116mm (4.6").
  
• If exchanged for the Butt Extension of 65mm (2.6"), the Leshiy 2 becomes 51mm (2") shorter
• If exchanged for the Butt Extension of 96mm (3.8"), the Leshiy 2 becomes 20mm (0.8") shorter
• If exchanged for the Butt Extension of 136mm (5.4"), the Leshiy 2 becomes 20mm (0.8") longer
• If exchanged for the Butt Extension of 156mm (6.1"), the Leshiy 2 becomes 40mm (1.6") longer

2020 Standard Regulator:

• Butt Extension from factory: 136mm (5.4")
  
• If exchanged for the Butt Extension of 65mm (2.6"), the Leshiy 2 becomes 71mm (2.8") shorter
• If exchanged for the Butt Extension of 96mm (3.8"), the Leshiy 2 becomes 40mm (1.6") shorter
• If exchanged for the Butt Extension of 116mm (4.6"), the Leshiy 2 becomes 20mm (0.8") shorter
• If exchanged for the Butt Extension of 156mm (6.1"), the Leshiy 2 becomes 20mm (0.8") longer

Also Includes:
- O-ring 18x2 (x2)
- Screw 4x6
- Ball 3MM