HENGQI PLAY vs Stringline

HENGQI PLAY is an APP that can realize real-time video transmission through WIFI connection to the car, remote control of the car, take photos and video

Construction calculator that works in feet, inches, and fractions — matched to 1/64". Download for free. No subscription. No ads. Works offline. 14 SPECIALTY CALCULATORS Stair Layout — rise, run, stringer, angle. IRC and OSHA code check built in. Concrete — cubic yards and bag counts for slabs, footings, columns. Rafter Length — common, hip/valley, jack. Plumb cut, seat cut, overhang. Equal Spacing — every position for studs, balusters, posts, joists. Compound Miter — blade tilt and miter angle for crown and trim. Studs / OC — count and positions for any wall at 16" or 24". Pitch / Slope — pitch, degrees, grade, and roof factor. Baluster Spacing — count, gap, and positions. IRC 4" sphere test built in. Board Feet — lumber volume from nominal dimensions. Drywall Estimator — sheets, waste factor, and opening deductions. Roofing Calculator — squares, bundles, and sheathing for any roof pitch. Right Triangle — check square on any corner. Two sides in, all angles out. Area & Volume — rectangles, circles, triangles, trapezoids. Conversions — feet-inches, decimal feet, metric. HOW IT WORKS Three calculators are yours to keep — Right Triangle, Area & Volume, and Conversions — with the full keypad, memory, and paper tape. No limits, no catch. The other 11 Pro calculators (stairs, concrete, rafters, and more) come with 5 uses so you can try them on a real job. One purchase unlocks everything permanently. YOUR TAPE READS FRACTIONS. SO DOES STRINGLINE. Enter 12' 3-1/2" exactly how you say it. No converting to decimals, no rounding surprises. Integer 64ths arithmetic — every answer matches your tape, not a floating-point guess. BUILT TO BE TRUSTED • Shows the math — step-by-step so you can verify every answer • IRC and OSHA validation with code section citations • Every formula verified against building code standards before release • Paper tape and full calculation history • PDF export with Show My Work steps • Works completely offline — no internet, no accounts No subscription. No ads. Built for tradespeople who can't afford a wrong number.