Heater Box for PTC element

Simple box with lid sized for a 77mm x 62mm x 6mm aluminum PTC heater element (e.g. https://www.aliexpress.com/item/1PCS-PTC-Thermostat-Aluminum-Heating-Element-Heater-Plate-60W-AC-DC-12V-180-Degree-Incubator-Dehumidification/32812440130.html)

Since I needed to go above 60°C, I cast mine from concrete (and printed the strain relief with XT). Files for the mold are included (I only needed one so I printed it from PLA as a single use mold).
If you want to use the cable guide, you need to put a 40x20x10mm spacer into the inner part of the mold (I used a block of Teflon). M3 nuts, M3 screws and small zipties are needed for the strain relief. Drill a 3mm hole through the base to attach the relief to the box with an M3 screw.

I designed two vial holders for this: https://www.thingiverse.com/thing:2891050