Tam Nak Sai Khmer Sanctuary consists of a single stupa on laterite base. The brick stupa has a rectangular shape with the doorway facing east while there are false doorways on the other three sides. Two carved guardian lions are watching the gate. The front door frame is made of sandstone. Over the door was a carved lintel depicting the God Narai lying on naga, with Laksami sitting at his feet, and Brahma rising from his navel. On both sides of Brahma are a hermit and a figure. The Narai Banthom Sin lintel is now kept in Phimai National Museum.

Source: onsite information