Finless-type drives do not have cooling fins, which are the main heat-dissipating component of the drive. The finless-type drive uses the enclosure panel (metal plate) as a cooling fin to release the heat generated by the drive. This will let you install the drive in a smaller enclosure panel.
Finless-type drives are recognized components by UL (Underwriters Laboratories Inc.).
Machines and devices integrated with this product must satisfy Conditions of Acceptability conditions for compliance with UL standards.