My first self-made sandal. Printed in Men's size 43 for use with any standard footbed. (But it also works without if necessary.) 

The pair of sandals costs less than €7.50 (plus electricity) at a TPU price of €25/kg. 

The filament I use is standard TPU 95A or high speed TPU

I have added a conversion table as a picture.

If you are unsure about the size, print a version in cheap PLA first and test whether the size fits.  That's what I did.

The straps can be adapted to your own Foot height and glued on accordingly.

I use cyanoacrylate superglue that is waterproof and achieves excellent results. 
(Cyanoacrylate adhesive is the best for bonding TPU)

Here are a few tips:

• Don't fasten the straps too tightly. Then they can become uncomfortable. It is best to wear thick socks when attaching them. 
• The high speed filament feels harder than the standard TPU. This makes the sandals slippery at first on smooth ground. I took them for a walk outside and afterwards the grip was normal again.
• The Tynmorry Standart TPU feels more comfortable than the Overture HS TPU
• Alternatively, you can use PU artificial leather for the straps. This is softer, but will stretch a little over time.
• The sandals are designed for over 100 kg.  For lighter people, I recommend reducing the infill and lowering the number of upper layers. Perhaps first make a 1 cm thick test print with the selected filament.
• I recommend gluing the strips to the outside first and then attaching them to the inside. Any excess can easily be cut off afterwards.

The sandal is still under development. I want to continue to improve the comfort and convenience and ultimately release a good, wearable and affordable shoe.

I hope you have fun with the slippers, please write me your experiences and suggestions for improvement.

- In the current version, I have reduced the infill to 11% and rounded off the edges of the belts.