Shop › Altis Sigma Underseat NFC key holder .STL file Altis Sigma Underseat NFC key holder .STL file $5.00 3d print your own hidden NFC Key holder for the Altis Sigma. You will receive the .STL file 3d print your own hidden NFC Key holder for the Altis Sigma. You will receive the .STL file Get notified by email when this product is in stock. Add To Cart Added!