Scalable Linear Recording is the name used by Tandberg Data for its line of QIC based tape drives.
The earliest SLR drive, the SLR1, has a capacity of 250 MB, while the latest drive, the SLR140, has a capacity of 70 GB. The term SLR is now often used to refer to QIC tapes, as they are the only drives still manufactured that use them.
NOTE: MLR stands for Multi-channel Linear Recording.