Abstract: An ear tip for an earpiece including a body, an insertion end, and a retention structure. Some examples include an elongated fin along a portion of an outer leg of the retention structure. Some examples include an extended insertion end configured to insert further into a user's ear canal and including a mushroom cap for providing contact with an interior portion of the user's ear canal and to form an acoustic seal. Some examples may include an umbrella associated with the insertion end, between the mushroom cap and the body. Electrically conductive elements may be associated with any of the elongated fin, the umbrella, and the mushroom cap, to provide electrical contact with the user's skin for sensing electrical signals or for delivery of electrical stimulation.

Abstract: An injection molded keep is disclosed that includes a thermoplastic material and a reinforcement material. The keep is positioned adjacent a top plate in a doctor blade holding apparatus and provides a slot opening between the keep and the top plate for receiving an end of a doctor blade in the slot opening.