The transportation of delicate items often requires greater control of cylinder acceleration and deceleration than is afforded by traditional air cushions. For this reason, SMC has developed the REC sine cylinder. The term "sine cylinder" is derived from the shape of the velocity curve at both ends of stroke. This control is achieved with the addition of two grooves on each cushion spear which results in a more gradual initial acceleration or deceleration and smooth transition to or from full speed operation. To accomplish this type of motion with a traditional cylinder typically requires extensive external flow control. REC is a repairable basic cylinder.