DSLR-Quality Smartphone Lenses : +Lens modular system
Baader 17mm Hyperion 68° Modular Eyepiece - Baader Planetarium UK
Lens Changer™ 75 Pop Down V3.0 case bag pouch for modular belt system – Think Tank Photo
Tasmanian Tiger TT Modular Lens Bag VL Insert S Padded Camera Lens Bag with Velcro Back Lens Case Inner Dimensions 11 x Diameter 8 cm (Black) : Amazon.co.uk: Electronics & Photo
Baader 13mm Hyperion Modular Eyepiece 2454613
ASKAR V Modular APO Telescope with 2 Interchangeable Lenses with 60mm and 80mm Apertures and 6 Possible Focal Lengths - ASKR-V
Askar V modular telescope kit - BBC Sky at Night Magazine