DGR 18.104.22.168 (a), (b) and (c) refer to the requirements of protecting the cylinder valve and (e) states that the cylinder itself must be packed into an outer packaging capable of withstanding a PG I drop test. Provided the cylinder is a UN certified cylinder or a cylinder that has been certified by the state in accordance with local regulation, the required handling is an overpack.
PI 200 also states that cylinders of less than 1L capacity must also be overpacked.
The declaration must show:
1 CYLINDER X 5.3kg
Which is the correct way to enter.
The above applies to when the cylinder is a UN certified cylinder (DGR Table 6.4.A) or the cylinder carries a local government certification (DGR 6.4.3).