In reference to Cryopen in question, and the N2O gas cylinder, N2O is Nitrous Oxide. Nitrous Oxide is used in surgery and dentistry for its anaesthetic and analgesic effects. It is known as “laughing gas” due to the euphoric effects of inhaling it. On 18 Feb. 2016, the Japanese Ministry of Welfare & Labor designated it as “Designated Drug” per Medicinal & Medical Device Law. Effective 28 Feb. 2016, except for medical use, N2O has been prohibited to be manufactured, sold, possessed and used.
Nitrous oxide is classified as “UN1070 Div. 2.2 (5.1) EQ code E0, LQ Forbidden, PAX PI200 75kg, CAO PI200 150kg.”
N2O in cryogenic liquid form is classified as “UN2201 Nitrous oxide, refrigerated liquid Div. 2.2 (5.1) and is Forbidden for air transport. It can only be exempted by securing special approval per SP A2.
In the States it is used as substitute for drugs.
Nitrous oxide is a substance far from being considered approved for passengers to carry as baggage. Furthermore, Medicinal or Toiletry Articles mentioned in DGR Table 2.3.A are primarily oral and/or dermal medicines and do not include medical devices.