In one embodiment, an apparatus includes a base plate having a first aperture to receive an inlet in fluid communication with a downhole tool; a compliant outer cover having a first end terminating at the base plate and a second end terminating adjacent a forward opening of the inlet, the compliant outer cover having a first surface configured to engage a borehole wall and a second surface forming an inner cavity with the base plate; and a core disposed within the inner cavity and having a second aperture forming at least a portion of the inlet, wherein the outer cover comprises a first material and the core comprises a second material more compliant than the first material.