Controllable gas caij nplooj ntoos hlav, tseem hu ua lockable gas caij nplooj ntoos hlav, lub kaum sab xis-adjustable gas caij nplooj ntoos hlav, tswj lub stroke los ntawm qhib thiab kaw lub valve, thiaj li hais tias tus mob stroke yuav tsum tau nres ntawm txhua txoj hauj lwm, thiab feem ntau yog siv rau rooj, txaj, rooj, rooj zaum. , xim teeb thiab lwm cov ces kaum, qhov twg qhov siab yuav tsum tau kho. Raws li kev kaw lub zog, nws tuaj yeem muab faib ua elastic locking thiab txhav txhav txhav, thiab txhav txhav txhav tuaj yeem muab faib ua compression locking thiab nro locking raws li cov lus qhia sib txawv.