BU-P72914-2 - Adapter: 4mm Banana Jack to 2mm Banana Plug - Mueller Electric
Amazon.com: heyous 2pcs Gold Plated 2mm Mini Male Banana Plug to 4mm Female Jack Connector Adapter (Color: 1red1black) : Electronics
Ymiko Banana Plug Adapter,5set Banana Plug Adapter PA Brass Material 2mm/0.08in Male To 4mm/0.16in Female Red Black Banana Connector,Banana Plug - Walmart.com
2) Banana Plug Adapter 2mm Female to 4mm Male
Amazon.com: Yohii Dahszhi Banana Male to Female Plug 2mm to 4mm Socket Probe Adapter - 2pcs : Electronics