Key benefits Monitor weather trends: the contrast marker on the acrylic lens lets you mark and compare recent barometer readings to see whether atmospheric pressure is rising or falling over time. Reliable environmental readings: separate precision sensors for temperature, humidity and pressure give the data needed to plan activities or respond to changing conditions. Durable, readable design: brass housing, metal pointers and an acrylic lens provide long-term stability, clear visibility and corrosion resistance in demanding environments. Ready-to-use set: four identical instruments allow simultaneous monitoring in multiple locations or redundancy for critical sites. What the product does (functions) Barometer with gear-driven movement and metal pointer for accurate atmospheric pressure measurement. Temperature sensing via a hair-spring element; measured range −30 to 50 °C with accuracy ±2 °C. Hygrometer using a wet hair sensing element; accuracy ±5% RH (specified accuracy window 40–70% RH). Includes a 1-second clockwork movement as part of the instrument mechanics. Contrast pencil/marker on the lens for easy visual comparison of previous vs current readings. Technical specifications Temperature range: −30 to 50 °C; accuracy: ±2 °C. Hygrometer accuracy: ±5% RH (40–70% RH). Barometer range: 950 to 1070 hPa; accuracy: ±5 hPa (980–1040 hPa). Housing: brass; bottom shell included. Lens: acrylic. Pointer: metal. Quantity: 4 pieces per set. Why customers need this product Provides a compact, mechanical solution to monitor temperature, humidity and atmospheric pressure without reliance on electronics or external power. The marker on the lens simplifies short-term trend tracking, letting you detect pressure changes that precede weather shifts. The brass construction and metal pointers make the instruments suitable for regular use in locations exposed to moisture or vibration. Practical applications / use scenarios Onboard a vessel: mount several units in the wheelhouse, crew quarters and cargo area to monitor pressure and humidity changes that affect navigation and cargo condition. Industrial or factory floor: place instruments in different production zones to verify stable environmental conditions for machinery or materials. Laboratory or workshop: use as a reference set for routine checks of temperature, humidity and pressure where precise electronic monitoring is not required. Home: distribute units across rooms to compare indoor climate and help manage ventilation or heating. Compatibility and installation Mechanical instruments require no external power; suitable for wall or panel mounting where visibility and access to the lens marker are convenient. The set of four allows flexible placement for multi-point monitoring or spare units for backup. Notes on performance Barometer accuracy is highest in the 980–1040 hPa band (±5 hPa); hygrometer accuracy is specified at ±5% RH in the 40–70% RH range. The contrast marker provides a simple, repeatable method to compare readings over hours or days.