Thank you for viewing. This is a Pixco Speed Booster (focal reducer) M42 mount lens to Micro Four Thirds adapter. This product is a speed booster type mount adapter that, when using M42 mount old lenses on Micro Four Thirds cameras, - Brings the angle of view closer to full-frame equivalent - Reduces the effective F-value to increase brightness. In particular, many M42 lenses have unique descriptive qualities, and by using this adapter, you can take advantage of "reduced cropping," "shallow depth of field," and "three-dimensional feel characteristic of old lenses." It has only been used a few times indoors, and both the appearance and optics are in relatively good condition. There are no problems with normal use, but due to the nature of speed boosters, the accuracy of the flange back, etc., cannot be guaranteed. Please understand this beforehand. Please check the condition of the product in the photos. Please consider this item, understanding that it is a used product. #Pixco #SpeedBooster #M42 #helios #jupiter #zeiss #jena #MicroFourThirds #bmpcc #bmpcc4k #lumix #olympus #oldlens #cinelens #cinemacamera #mountadapter