A hardcoat for a plastic substrate film is provided which has good suitability for printing and satisfactory hardness, can prevent influence of the deformation of a plastic substrate film from extending to the hardcoat, and is resistant to cracking and peeling. The unit has a first portion configured to mount in a vehicle radio mounting location and a second portion configured to extend significantly outside the vehicle radio mounting location. 1 to 100 parts by weight of a layered silicate,wherein a combustion residue thereof obtained by combusting said polyolefin resin composition by heating for 30 minutes under heating condition of 50 kWm2 shows a yield point stress of not less than 4. Other embodiments are described. A second slot is also preferably provided, disposed below the upper surface, for cutting tool storage.