Dräger X-zone 5000 Notice D'utilisation page 262

Notes on Approval
Marking
1
Serial No.
1 The year of manufacture is indicated by the third letter in the serial
number: B = 2010, C = 2011, D=2012, E=2013, F=2014, G=2015,
H=2016, I=2017, J=2018, etc.
Example: Serial No. ARBH-0054: the third letter is B, which means
that the unit was manufactured in 2010.
262 Dräger X-zone 5000