Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter
StarTech.com TBT3TBTADAP Thunderbolt 3 to Thunderbolt 2 Adapter - Backward Compatible - USB C to Mini DisplayPort - USB-C to Thunderbolt 2 - Newegg.com
Apple MMEL2AM-A Apple 純正アクセサリー【Thunderbolt 3/USB-C/Thunderbolt 2アダプタ】 | ノジマオンライン
Apple Thunderbolt 2/Thunderbolt 3 Data Transfer Cable for Hard Drive, MacBook Pro - First End: 1 x USB Type C Male Thunderbolt 3 - Second End: 1 x Female Thunderbolt 2 - Hunt Office Ireland