Asymmetrical rail volume. One side is more positive than the other. Available in various lengths. Width x Height x Length
 
Shipping for individual volumes is NOT free. 
 
XS12- 5"x4.5"x12" $65
XS18- 5"x4.5"x18" $80
S24- 5"x4.5"x24" $100
S30- 5"x4.5"x30" $120
M36- 5"x4.5"x36" $150
M48- 5"x4.5"x48" $160
L60- 5"x4.5"x60" $170
L72- 5"x4.5"x72" $180
XL84- 5"x4.5"x84" $190
XL96- 5"x4.5"x96" $200
XXL120- 5"x4.5"x120" $250
XXL144- 5"x4.5"x144" $280
 
Package
2- XS12- 5"x4.5"x12" $65
2- XS18- 5"x4.5"x18" $80
2- S24- 5"x4.5"x24" $100
2- S30- 5"x4.5"x30" $120
2- M36- 5"x4.5"x36" $150
2- M48- 5"x4.5"x48" $160
Retail- $1,350
Package Price- $1,199