Uniform Cross Section Mattress
The Uniform Cross Section Mattress has no Filter Points, with the two layers of fabric being held together by diagonal restraining ties spaced at regular intervals. As a result it inflates to a constant thickness to act like a nominally, fibre-reinforced concrete slab, forming an impermeable lining.

This mattress has a much smoother finish giving a Manning's 'n' of approximately 0.016. It is best suited to situations where a low Manning's coefficient or impermeability is a requirement, commonly including structures such as dams, holding reservoirs, boat ramps and channels. It also allows for traffic from maintenance vehicles without any damage to the integrity of the system as well as preventing the flow of water without the need for an impermeable liner.