Amazon.com: Adapters(16mm) and 1 Piece HD Conversion RAF NATO Nylon Watch band Strap Kit For Casio GShock MIL-SHOCK 5600 GWM5610 DW6600 GW6900 2310 G100 (Red) : Clothing, Shoes & Jewelry
PSA (YMMV) Amazon Warehouse GW-M5610-1 (GW-M5610U) used like-new for $77 : r/gshock
Amazon.com: Canvas Quick Release for Compatible G-SHOCK Watch | 100% Cotton Crafted Canvas | Black PVD adapters, Black PVD buckle, two 16mm spring bars, two 22mm spring bars (Standard, Army Green) :
Amazon.com: Casio Men's GW-M5610-1BJF G-Shock Solar Digital Multi Band 6 Black Watch : Clothing, Shoes & Jewelry
Casio G-Shock GWM5610-1 Review: The O.G. G-Shock Is Still the Best
Amazon.com: Lijinlan Strap Compatible with Casio G-Shock, Men Nylon Replacement Watch Band for G-Shock DW5600/GWM5610/DW6900/DW9052/GW100/GA100/GD120/GA400 : Clothing, Shoes & Jewelry
G-Shock GW-M5610NASA4 x NASA Collaboration
The GWM5610-1CR is on sale for $80 at Amazon : r/gshock