H.Koenig BW1880 Manuel D'utilisation page 5

*The sealants with code No. 22 need to be removed off the marking
ring from the sealant and pierce the keg by cooler piercing pin.
(Show as figure 1)
*The difference between code No 23 and 24 is the safety clasp
quantity. Pull up the safety clasp carefully, turn around and take it out
from the keg; replaced it by the sealant (like code No 2 sealant)
provided in the beer cooler, attach it to the beer keg, and pierce it by
cooler piercing pin. (Show as Figure 3).
Figure 1
(Important: Before replacing the sealants or piercing the cooler kit,
you must always follow the instructions marked on the keg to
eliminate the excess gas and ensure that the keg has rested long
enough to avoid foam coming out through the cooler piercing pin /tap
faucet. And it is no need to release the gas and replace the seal
rubber if you use Heineken keg, because Heineken keg has its own
CO2 pressure inside, and no need to be provided from outer CO2
pressure system.