@FearDaToof First entry for Thailand I've seen in the Tank Encyclopedia:

https://tanks-encyclopedia.com/coldwar/thailand/porborkhor-105-attajhon/

Porborkhor 105 Attajhon - Tank Encyclopedia

The Porborkhor 105 Attajhon was the first self-propelled artillery gun (SPAG) to see service in the Royal Thai Army. It was also one of the early steps of the Thai defense industry. The SPAG was built combining old weaponry to solve issues of a lack of artillery mobility and the inability to acquire foreign vehicles.

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