Invacare HomeFill II Operator's Manual page 25

SECTION 4—COMPRESSOR OPERATION
8. Pull UP on the outer ring (sleeve) of the connector fillport
while pushing DOWN on the cylinder/regulator assembly
to couple the cylinder fillport into the connector fillport
(FIGURE 4.2).
NOTE: The cylinder is properly connected when an audible "click"
is heard.
HomeFill II Compressor
™
25 Part No 1100873