A putter-type golf club head comprising: a chassis and a putter type body ; wherein the chassis comprises a first material comprising a density of at least 7 g/cm3; wherein the body comprises a second material comprising a density of 4 g/cm 3 or less; the chassis further comprises: a heel portion , a toe portion , a rear , a front , an upper surface , and a lower surface ; wherein the heel portion is opposite the toe portion and adjacent to the rear ; wherein the upper surface is opposite the lower surface ; wherein the front is adjacent to the toe portion and the heel portion , and opposite the rear ; wherein a central strut spans from the heel portion to the toe portion opposite to the rear ; wherein the heel portion , the toe portion , the rear , and central strut form a flow aperture ; at least one interlocking feature ; wherein the body encases the entirety of the at least one interlocking feature ; and wherein the body completely surrounds the chassis such that the body extends through and completely fills the flow aperture , to interlock the body and chassis , and to form the club head . a chassis and a putter type body ; wherein the chassis comprises a first material comprising a density of at least 7 g/cm3; wherein the body comprises a second material comprising a density of 4 g/cm 3 or less; the chassis further comprises: a heel portion , a toe portion , a rear , a front , an upper surface , and a lower surface ; wherein the heel portion is opposite the toe portion and adjacent to the rear ; wherein the upper surface is opposite the lower surface ; wherein the front is adjacent to the toe portion and the heel portion , and opposite the rear ; wherein a central strut spans from the heel portion to the toe portion opposite to the rear ; wherein the heel portion , the toe portion , the rear , and central strut form a flow aperture ; at least one interlocking feature ; wherein the body encases the entirety of the at least one interlocking feature ; and a heel portion , a toe portion , a rear , a front , an upper surface , and a lower surface ; wherein the heel portion is opposite the toe portion and adjacent to the rear ; wherein the upper surface is opposite the lower surface ; wherein the front is adjacent to the toe portion and the heel portion , and opposite the rear ; wherein a central strut spans from the heel portion to the toe portion opposite to the rear ; wherein the heel portion , the toe portion , the rear , and central strut form a flow aperture ; wherein the heel portion is opposite the toe portion and adjacent to the rear ; wherein the upper surface is opposite the lower surface ; wherein the front is adjacent to the toe portion and the heel portion , and opposite the rear ; wherein a central strut spans from the heel portion to the toe portion opposite to the rear ; wherein the heel portion , the toe portion , the rear , and central strut form a flow aperture ; at least one interlocking feature ; wherein the body encases the entirety of the at least one interlocking feature ; and wherein the body completely surrounds the chassis such that the body extends through and completely fills the flow aperture , to interlock the body and chassis , and to form the club head . <EOS>