GF DSR 500-1 Manuel D'utilisation page 35

For version without window only the adapter ring with o-ring is attached to the valve.
(Check the distance Yu, see below).
For the version with window the adapter ring with O-ring is attached to the valve.
Then screw the attachment kit to the pneumatic valve.
Check the distance H, see below.
35
Yu= distance required for correct
installation of adapters
H= distance required for correct
installation of adapters