The limit for Royal Mail Large Letter is 25mm tall, and unfortunately the Arduino DCC Interface Shield and DCC TurnTable Interface for Uno are 23mm tall.
When in a jiffy bag, its very close to the limit for Large Letter – and for some Post Office Employees this is too thick, and other Post Offices Employees its fine….. so until i can find a better solution ( change the capacitors perhaps , or a small box ) I will have to increase postage on these items.
