{"product_id":"shimano-sm-jc40-41-di2-junction-box","title":"Shimano SM-JC40\/41 Di2 Junction Box","description":"\u003cdiv\u003e\n\u003cp\u003eThe \u003cstrong\u003eShimano SM-JC40\/41 Di2 Junction Box\u003c\/strong\u003e is the four-port hub that sits at the heart of a Di2 wiring setup — routing connections between the battery, front derailleur, rear derailleur, and Junction A at the stem. Two variants cover the two standard installation approaches: the SM-JC40 mounts externally beneath the bottom bracket shell using the cable guide bolt (two bolt sizes included), while the SM-JC41 sits inside the frame, typically in the downtube or seat tube, secured with double-sided tape or left to rest freely given its compact, lightweight form.\u003c\/p\u003e\n\u003cp\u003eBoth boxes use Shimano's plug-and-play EW connector system, making routing and installation straightforward whether you're building a new Di2 drivetrain or replacing an existing junction box.\u003c\/p\u003e\n\u003cul class=\"specs_at_a_glance\"\u003e\n\u003cli\u003e\n\u003cstrong\u003ePorts:\u003c\/strong\u003e 4-port configuration\u003c\/li\u003e\n\u003cli\u003eSM-JC40 — External mount, bottom bracket shell\u003c\/li\u003e\n\u003cli\u003eSM-JC41 — Internal mount, frame routing\u003c\/li\u003e\n\u003cli\u003eCompatible with Shimano Di2 electronic drivetrains\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e","brand":"Shimano","offers":[{"title":"No Color \/ External","offer_id":43520527958060,"sku":"ISMJC40","price":24.99,"currency_code":"USD","in_stock":true},{"title":"No Color \/ Internal","offer_id":43520527990828,"sku":"ISMJC41","price":24.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0608\/7684\/9196\/files\/shimano-sm-jc4041-di2-junction-box-5424279.jpg?v=1771297328","url":"https:\/\/ricycles.com\/products\/shimano-sm-jc40-41-di2-junction-box","provider":"RA Cycles","version":"1.0","type":"link"}