瑜伽師地論略纂 2.104

2.104

Regarding 'rollers and stones free from vitarka and vicāra' and so forth: these are all instruments for massage and physical adjustment. Either one uses stones and the like to roll over the body sequentially from head to foot, making the body comfortable; or one uses rollers to rotate over the body, and stone pestles and the like to strike and pound the body to achieve comfort. Since the nature of these [objects] is entirely free of vitarka and vicāra, they are called 'free from vitarka and vicāra'.