Specifications:
Commonly used line width reference (unit: mm)
Angle measurement: 180 degrees
Device, IC pin spacing table: 0.5mm, 0.65mm, 0.8mm, 1.0mm, 1.25mm, 2.54mm;
Common bore diameter reference dimensions (unit: mm): 3.0 2.5 2.0 1.5 1.0

Commonly used SMD component packaging (take 25CM ruler as an example):
①Resistor capacitor SMD package: 0603, 0805, 1206, 1210, 2512, RES-4, RP3x3
②Diode SMD package: SOD-323, SOD-123, 4, ED5, ED6.3, ED8, ED10, ED12.5
⑦ Commonly used chip inductor packages: CD43, CD54, CD62, CD75, CD12x12
⑧ Commonly used SMD crystal packages: 3215, 3225, SM49, TC26
⑨ Commonly used SMD C packages: SOP-4, SOP-8, SOP-8W
SOP-8A, SOP-14, SOP-16, SOP-18, SOP-20
SOP-24, SOP-32, SOP-24, QSOP-24
SOP-48, LQFP-44, LQFP 48, LQFP-100
LQFP-144, FBGA64, BGA DDR 3RAM
⑩ Commonly used SMD light-emitting diode packages: LED-2, 0603LED,
0805LED, 2835, 3528, 3535, 5050, LED-1W
Commonly used patch FPC cable holder package: FPC-40p-0.5MM, FPC-30P-1.0mm, FPC-40p-1.0mm

Package includes:
1 x 15cm PCB Ruler
1 x 20cm PCB Ruler
1 x 25cm PCB Ruler