... ,pls let us know the parameters .specifications:Usage: office chair,medical bed,office sofaFeatures: 1, Gas: Nitrogen filled inside. 2, Color : black,silver,or ... oil; Our paint is passed ROHS test; 4,When the gas spring is up and down, it's soomth opration without noise ... after deposit.Shipment: We can accept your appionted forwarder. lockable gas spring for office chair