A Bore Gage is used to measure the inside diameter of a hole or cylinder. This explains why it is referred to by so many different names. You are actually measuring the bore size. A bore is simply a hole and a bore gage measures the internal diameter of the hole
 

NSIZE 2322-35A DIAL BORE GAGE 18-35MM

• Optional accessory : Setting ring (code 6312), Long handle (code 7351)
• Range : 18 - 35mm
• Dial indicator range 10mm, graduation 0.01mm
• Accuracy : +-0.018
• Repeatability : 0.003mm
• Feature : ceramic contact point, ceramic anvil

Insize Bore Gauges #2322-60A 35MM - 60MM

1️⃣Range: 35-60 mm

2️⃣Indicator: Dial Indicator, range 10mm, graduation 0.01mm

3️⃣Accuracy: +/- 0.018 mm

4️⃣Repeatability: 0.003 mm

INSIZE 2322-100A DIAL BORE GAGE 50-100MM

• Optional accessory : Setting ring (code 6312), Long handle (code 7351)
• Range : 50 - 100mm
• Dial indicator range 10mm, graduation 0.01mm
• Accuracy : +-0.018
• Repeatability : 0.003mm
• Feature : ceramic contact point, ceramic anvil

 Dial Bore Gauge #2322-160A

1️⃣Range: 50-160 mm

2️⃣Indicator: Dial Indicator, range 10mm, graduation 0.01mm

3️⃣Accuracy: +/- 0.018 mm

4️⃣Repeatability: 0.003 mm
 

Insize 2322-250A Bore Gauge 160~250mm x0.01mm