Gland Packing (500mm length)
Length is for a 500mm length. This is not graphite impregnated , (you must not use graphite impregnated on marine propeller or pumps. )
The 5mm and 6mm is the newer PTFE synthetic, which readily accepts shaft speeds up to 1885 rpm and temperature to 260 degrees Celsius.
Measurement represents the square width of the packing. When installing don't coil it like a spring, cut it into rings with the joins in different places - like cylinder rings. If the size you have is slightly too small or too large, it can be hammered then slid in.
If you need a longer length please enquire.