However, unlike your average gas shock, the Gas-A-Just is a monotube design with no outer oil reservoir. There is a piston attached to the shock rod, and then the gas and oil are separated by another separate floating piston, which cushions but completely divides the two. So, the oil can never aerate with gas under heavy use like it will with your average KYB GR-2, Gabriel, or Monroe shock absorber.
They're similar--almost identical--to Koni and Bilstein monotube shocks. All three are vastly superior to anything offered by Gabriel or Monroe (especially the Monroe Sensa-Trac, or as we like to call it, "the brand-new worn out shock").