Altimeter, Japanese Naval Aviation, Sensitive Model 2, 10,000 M

This specimen of the Model 2 Sensitive Altimeter is made by Tanaka.  The scale is interesting in that the long pointer rotates clockwise from the 6 o'clock position indicating altitude in 100 Meters per index tick mark along the outer scale.  Once the aircraft reaches 5000 Meters, the short pointer begins to rotate clockwise, indicating altitude up to 10,000 Meters along the small inner scale.  The knob adjusts the accuracy of the reading by calibrating the instrument to the current barometric pressure as shown in the small window above center.  This Altimeter was used in aircraft of the Japanese Navy (see anchor on data plate) during WWII, including*:

• Aichi E16A Type 2 Reconnaissance Seaplane Zuiun aka "Paul"
• Aichi E13A Type Zero Reconnaissance Seaplane aka "Jake"
• Aichi B7A Torpedo/Dive Bomber Type 99 Ryuusei-Kai aka "Grace"
• Aichi M6A Submarine-launched Attack Seaplane Seiran
• Kyushu Q1W Anti-submarine Bomber Tokai aka "Lorna"
• Nakajima C6N Carrier-based Reconnaissance Plane Saiun
• Nakajima G5N Bomber Sinzan
• Nakajima J1N Bomber Gekko aka "Irving"
• Nakajima B5N Torpedo Bomber Type 97 aka "Kate"
• Yokosuka P1Y Bomber Ginga aka "Frances"
• Yokosuka D4Y Dive Bomber Type 1 Suisei aka "Judy"

*According to Funatsu Aviation Instruments Museum

The outer case is clearly 'experienced' as evidenced by some corrosion and chipped paint.  The knob does not rotate, but could possibly be serviced.  Measures ~3.25 inches diameter by ~4 inches deep.