This Zenith Respirator AF/P features a 36,000 BPH 405 calibre automatic movement used by Zenith and Movado with a 40 hour reserve. It’s a high beat and watching the second hand move is genuinely mesmerising! French day and quickset date. Brushed dark brown dial with a signed Zenith NSA bracelet – I undervalued these straps but damn it’s comfortable.

AF/P stands for Alta Frequenza Precisione. Which is Italian for High Frequency Accuracy. I find it odd that this Swiss watch features a French day wheel with an Italian reference to the movement.

Now this is where it gets hazy – I believe the Respirator models were a two piece construction that was supposed to aid in water resistance considering it is of a square shape. The upper sat on a seal and as pressure increased it would clamp tighter – apparently great at high pressure but not so effective at lower pressures. The concept is very similar to the original Omega Marine watch – possibly the first dive watch in 1932.

This is an X model where I have read they stopped doing this two piece construction as it was not as successful as expected.