NEWYI Adjustable Focus Helicoidal Adapter, Macro Extension Tube for Camera M42‑M39

[ADJUSTABLE FOCUS HELICOID ADAPTER] The best choice for magnifying or modifying lenses. Provides focusing for lenses without focus. [MACRO TUBE WITH END OF FOCUS CONTROL] Can be used as a macro tube to provide precise focus control for macro photography. [DURABLE AND EASY TO USE] Made of aluminum alloy with black anodized finish. M42 and M39 threaded interfaces are universal and easy to transfer. [RECEIVE ALMOST PERFECT IMAGES] The matte inner wall of the focusing helical tube prevents the influence of reflected light on the imaging. [ADJUSTABLE FOCAL LENGTH 17MM-31MM] Offers an adjustable distance of 14mm for focus' lens.