2 pairs Yellow replacement 4 x 1.9 folding 2blade propellers, compatible with Gemfan F4019 Floppy Proppy 4019. Precision molded PC construction for quieter, more efficient flight on 4 inch LR4 micro long range drones and similar builds. Key benefits Quieter operation: twoblade folding design and balanced PC material reduce noise for smoother, less intrusive flights. Stable thrust and responsive control: 1.9 inch pitch and 102.06 mm diameter deliver consistent momentum and predictable handling. Lightweight and efficient: each propeller weighs 1.42 g for lower rotating mass and improved energy efficiency. Easy mounting and quick release: T mount center hole and a 5.5 mm center thickness for fast installation and removal during maintenance or swap outs. Durable and smooth: higher tension construction gives reliable durability while maintaining smooth, responsive performance. Specifications Quantity and color: 2 pairs, Yellow Material: PC Propeller diameter: 102.06 mm Pitch: 1.9 in Center thickness: 5.5 mm Center hole: T mount Recommended motor range: 1505 up to 3500 kv Weight: 1.42 g per propeller Other available colors: Clear Gray, Milk White Practical use scenarios damaged props on a 4 inch LR4 micro long range drone to restore quiet, efficient cruise performance. Test quieter propeller setups during long range flights where reduced noise and energy savings extend runtime. Use as spare parts for DIY FPV racing builds that pair 1505 to 3500 kv motors with F4019 style mounting. Compatibility note Compatible with F4019 Floppy Proppy 4019 series prop mounts and similar 4 inch foldable propeller systems that use a T mount. This set provides a straightforward replacement or upgrade option for pilots seeking quieter, more efficient flights without changing motor or frame hardware.