The crown protector on the PloProf looks like a vault door. However, there is no external mechanism needed to lock or unlock the guard. Instead, you just need to unscrew the crown like you would any other crown. The front part of the closed protector moves along with the crown, which is easy to grasp and turn. The crown operates smoothly when you spin it. Winding is predictably smooth and quiet and there is no danger of cross-threading at all.
Another professional diver watch that I own that has a similar shaped crown protection (difference mechanism) in the same location (at 9 o’clock position) is the Citizen Autozilla. Due to the design of the crown guard, the PloProf is not as painful to the skin as compared to the Autozilla’s if it digs into the wrist.
Adjusting the time and date via the crown is slightly different than typical watches. When the crown is in its second extracted position, it can be used in the usual way to adjust the hour hand and minute hand and activating the stop-seconds function (hacking). In its first position, it can be turned to reposition the hour hand in single-hour increments while the seconds hand keeps running, which also resets the date display by moving it forward and backward. Thus, the date can be quickly reset even though the watch doesn’t include a quick-set function for the date display. This independently adjustable hour hand is practical when the wearer travels to a new time zone often.
The PloProf has an automatic helium valve so that professional divers can wear it during saturation dives. The valve is positioned on the underside of the orange button’s position and marked with the chemical abbreviation “He” (for helium) beneath a coating of clear lacquer. I doubt I will ever reach the necessary depth for the valve to pop. Like airbags in cars, its good to know that you have it but it is even better if you don’t ever need to use it.
The case back is art. With a central engraved and ridged disc that is held in horizontal orientation by an outer compression ring. The ridges on the central disc and the engraved center with the legendary Seamaster hippocampus were beautifully rendered. It provides the necessary texture to keep the watch from slipping around the wrist.
The strap is the most difficult to resize in my opinion. If you have gotten the PloProf with the Milanese (mesh) metal “shark-proof” bracelet, resizing is a just a matter of taking out the necessary number of links. However, if you got the rubber strap, which I did, resizing means cutting!!!
