malykh.com notes: Noname Leica M-Sony FE/E close focus (helicoid) adapter
M42 To M42 Focusing Helicoid Ring Adapter 12 - 17Mm Macro Extension Tube(1Pcs) | Lazada PH
KECAY M42 (42mm) to 42mm Mount Focusing Helicoid Ring Adapter 17mm - 31mm(Black): Amazon.co.uk: Electronics & Photo
M42-M42(17-31) M42 to M42 Mount Lens Focusing Helicoid Adapter Ring 17mm-31mm Macro Extension Tube | Lazada PH
M427-31mm Focus Lens Mount Adapter, 14mm movement distance for lens focusing | Walmart Canada
Fotasy 35-90mm M42 to M42 Lens Macro Helicoid Adapter, 42mm Focusing Helicoid Extention Tube, 35mm to 90mm, 55mm Max Movement, fits M42 Screw Mount Lens | Amazon price tracker / tracking, Amazon
M58 to M42 Focusing Helicoid Ring Adapter 25-55mm Macro Extension Tube - AliExpress
Brass M42 to M42 Mount 25mm-55mm Adjustable Focusing Helicoid Adapter Macro Tube | eBay
M39/L39-Fujifilm X Macro Focusing Helicoid Adapter | Pixco - Provide Professional Photographic Equipment Accessories
Helicoid Adapter, Helicoid M42 M42 To M42 Adjustable Focusing Helicoid Lens Adapter M42 Helicoid Adapter, Macro Helicoid Adapter 17-31mm for Photographers
M42 to M42 Focusing Helicoid Ring Adapter 12 - 17mm Macro Extension Tube(2Pcs) | Lazada PH
Helicoid focusing explained, for mirrorless digital cameras - YouTube
A Warning to Those Who Are Using Helicoid Adapter: Adapted Lens Talk Forum: Digital Photography Review
M65 to M65 25-55mm Adjustable Focusing Helicoid Adapter Macro Tube 25mm-55mm | eBay
Lyla M42 to M42 Adjustable Focusing Helicoid Macro Extension Tube Adapter 25-55mm Standard Zoom Lens - Lyla : Flipkart.com
Leica M-Fujifilm X Macro Focusing Helicoid Adapter | Pixco - Provide Professional Photographic Equipment Accessories
Lens Bubbles: Using a Focusing Helicoid as a Lens Adapter
/product/33/397373/1.jpg?0988 "Generic Brass M42-M39 17mm-31mm Adjustable Focus Helicoid Adapter @ Best Price Online | Jumia Egypt")