It is the Cure connector from Kaneka Co. www.kaneka-med.jp/medicalstaff/products/1_intervention/8_relation/2_accessories/1_cure-connector/ OKII connector from NIPRO Co. is another one that has a yellow valve. med.nipro.co.jp/med_eq_category_detail?id=a1U5F000021Y8WQUA0&name=Y%E3%82%A2%E3%83%80%E3%83%97%E3%82%BF%E3%83%BC%EF%BC%8F%E3%82%A2%E3%82%AF%E3%82%BB%E3%82%B5%E3%83%AA%E3%83%BC