Sanda goyon baya wani abu ne na roba tare da gas da ruwa a matsayin matsakaicin aiki. Ya ƙunshi bututu mai matsa lamba, fistan, sandar fistan, da adadin haɗin gwiwa. Ciki na sandar tallafi yana cike da nitrogen mai girma. Matsakaicin daidai yake, amma wuraren ƙetare a bangarorin biyu na piston sun bambanta. Ɗayan ƙarshen yana haɗi zuwa sandar fistan kuma ɗayan ƙarshen ba haka bane. A karkashin aikin matsa lamba gas, an haifar da matsa lamba zuwa gefe tare da karamin yanki na giciye, wato, ƙarfin roba na sandar tallafi. Saita tare da matsi na nitrogen daban-daban ko sandunan piston na diamita daban-daban. Ba kamar maɓuɓɓugan inji ba, sandar goyan bayan tana da lanƙwan roba kusan madaidaiciya. Matsakaicin ƙididdiga na X na daidaitaccen sandar tallafi yana tsakanin 1.2 da 1.4. Za a iya siffanta sauran sigogi cikin sassauƙa bisa ga buƙatu da yanayin aiki.