Na'ura mai ƙarfi ta F, F90 shine injin motsa jiki na tashar Dual guda ɗaya, watau horar da Prone Leg Curl da Extention Leg akan na'ura guda ɗaya.wanda aka tsara tare da dacewa, mai sauƙin daidaita kushin ƙafar ƙafa da kushin shinfiɗa daga wurin zama.Ƙirar kushin ƙafar ƙafar ƙafar ƙasa-da-gwiwoyi yana sauƙaƙe tsari mai kyau na ƙafar ƙafa.Masu motsa jiki na iya sauƙaƙe nauyin ƙarawa tare da sauƙi na turawa na lefa don ƙara nauyin aikin.