Harrow's main blueprint is awarded from the Chains of Harrow quest. Component blueprints are obtained from Spy and Survival missions on the Kuva Fortress, Defection missions, and Corrupted Void Fissure enemies.

Item	Count	Source
Harrow Neuroptics	1	Kuva Fortress/Pago (Spy), C 11.28%
Harrow Chassis	1	Void Fissure Corrupted Enemy 3.00%
Harrow Systems	1	Neptune/Yursa (Defection), C 11.28% Saturn/Caracol (Defection), C 11.28% Phobos/Memphis (Defection), C 7.52% Neptune/Yursa (Defection), B 2.01% Phobos/Memphis (Defection), B 2.01% 1 more…
Kuva	2,000