OVERALL DESIGN The study is a prospective, multicenter, single arm study Possible study candidates are patients requiring resection of the left colon (descending colon and sigmoid) or the upper rectum (15cm above the anal rim) due to malign or benign disease. After physical examination, checking of inclusion/exclusion criteria, and after informed consent has been achieved, potential subjects will be enrolled in the study, and the investigational surgery will be performed during hospitalization. The devices, i.e. C-REX LapAid and C-REX DMH/DMHC (dual male handle/dual male catheter handle), included in C-REX Ring-locking Procedure are applied to the inside of the intestine and connected to catheters that allow monitoring of the anastomosis (if DMC is applied).