Standard test temperature: 20 ℃, humidity: 70%. If test results show no variation, testing may be performed under normal ambient temperature and humidity. Current sensitivity: Pointer scale range is from zero to full scale; sensitivity is 960 µA ± 8%. Internal impedance: 650 Ω ± 10%. Insulation resistance: ≥ 50 MΩ at 500 V DC between case and circuit. Zero position: The front end of the pointer aligns with the center of the zero scale mark; tolerance: ±1 mm. Balance: When tilted forward or backward by 90° from default position, allowable error is ±1 mm. Pointer sticking: When subjected to triple full-scale current momentarily, then gradually reduced, the pointer returns to one-third of the scale. Friction: When current is gradually increased or decreased, indication error is within ±1 mm. Pointer swing direction: Left to right. Needle length: 44 ± 1 mm (from pivot center to tip). Pointer width: 0.45 ± 0.05 mm. Mounting orientation: Vertical. Operating temperature range: –10 ℃ to +60 ℃, RH 35% to 85%. Storage temperature range: –20 ℃ to +60 ℃, RH 35% to 85%. Avoid direct sunlight exposure. Store in packaging to prevent contamination. Soldering condition: Terminals immersed in molten solder (230 ℃) for 3.5 seconds to a depth of ~3 mm; device remains functional post-test. Soldering iron temperature: 350 ℃; contact time: 3.5 seconds; contact point: ~3 mm from terminal tip; device remains functional post-test. Electrostatic discharge test: Performed using dry nylon cloth on surface.