I purchased two nest boxes from the Nowra bird sale. They include inspection holes and climbing structures. The more upright one was specifically a Ringneck box and I have chosen to use the L shaped box for my Princess Parrots.
I have filled each with one third of saw dust.
The Ringnecks boxs dimensions are 45cm high x 25cm length x 25cm width.
The Princess Parrots boxs dimensions are 40cm high x 40cm length x 20cm width.
I introduced both boxes on the 24th July. My female Indian Ringneck has already started working the box.