A simple sleeve printed in thick TPU 95A - enough space for a passport and some bank notes/ credit cards
There is a plug to go in the end and it is sealed with a padlcock and secured with a chain or steel security cable.
While someone with a hacksaw or sharp knife could eventually open this , it would probably take them a long time
I made a blue version of the thicker passport safe - this has a matching 6mm coated 1m steel cable and steel washers each side to make it even harder for someone with a hacksaw.
Two new files are for a Large version with internal dimensions of 123 x 170 x 9 mm this takes around 21 hours in total to print in TPU95A at 100% infill - main part prints vertically with a 20mm brim (on the A1 ,not on the A1 Mini) - photo added of original with large comparison