Embodiments pertain to a downhole tool that includes a mandrel made of composite material; a first slip disposed around the mandrel; a first cone disposed around the mandrel, proximate to the first slip; a second slip disposed around the mandrel; a second cone disposed around the mandrel, proximate to a first side of the second slip; a sealing element disposed around the mandrel, between the first cone and the second cone; and a lower sleeve disposed around the mandrel, proximate to a second side of the second slip, wherein the first slip comprises a circular slip body having one-piece configuration with at least partial connectivity around the entire circular slip body; and at least two grooves disposed therein, wherein the circular slip body is made from filament wound material, wherein the circular slip body comprises a plurality of inserts disposed therein, and wherein at least one of inserts comprises a flat surface.