Small cell fragments of Megakaryocytes. Created from GATA 2 and GATA 1 factors and cytokines TPO, EPO and IL-3. Half life of 7-10d. lack a nucleus. Have mitochondria use glycogen for energy. Membrane bound glycoproteins BP1b and 11b/11a for adhesion and aggregation. At rest are smooth and non-sticky once activated become spiky and stick to injured surfaces.