Maybe one of these similar products would be of interest:-

MHW-3BOMBER Yu Series 58mm Dosing Funnel, Espresso Dosing Ring with 36 magnets, outer card slot Design, Coffee Dosing Ring anti slip for 58mm Portafilter, Espresso&Barista Accessory, Model: T5830-OS

MHW-3BOMBER 58mm Magnetic Dosing Funnel,Espresso Dosing Funnel Outward Locking Design,Coffee Powder Dosing Rings with10 magnets,Coffee Dosing Ring for Espresso&Barista Accessory, Model:DR5546B

MHW-3BOMBER 54mm Dosing Funnel, Espresso Dosing Ring with 10 magnets,Outward Locking Design,Coffee Dosing Ring for 54mm Portafilter, Espresso Coffee Machine&Barista Accessory, Model: DR5547B

Universal Principles of Design, Updated and Expanded Third Edition: 200 Ways to Increase Appeal, Enhance Usability, Influence Perception, and Make Better Design Decisions (1) (Rockport Universal)

PGA TOUR Golf Multi Tool - Golf Marker, Divot Repair Tool, Club Groove Brush, Magnetic Ball Marker, Golf Ball Markers for Putting Green, Pen, Keyring, Lightweight and Portable Golf Accessory