This headrest without cover fits several classic Volvo models, e.g., Amazon, 1800, 140 (model years 1965-1971), as well as the rear seat of Volvo 164.
The headrest is designed for easy installation in cars with headrest support consoles and provides an authentic appearance.

For older 1800 models, a special bracket must be welded to the frame for proper fit.

1800:
Can be installed on cars made after October 1968 with consoles for the headrest supports.
LHD: Ch # 28782 and later
RHD: Ch # 28639 and later

Headrest installation guide