An assembly comprising: a cylinder having a body with a wall forming a fluid inlet passageway and a wall forming at least one fastener receiving passageway, the fastener receiving passageway being in communication with the fluid inlet passageway; an adaptor comprising a wall having a proximal end and a distal end, the wall including a first portion adapted to mount to an associated source of a fluid medium and extending from the proximal end, a second portion adapted to be engaged with an associated tool which can apply a torque to the adaptor, the second portion extending from the first portion, a third portion extending from the second portion, the third portion seated within the fluid inlet passageway of the cylinder and sealed to the wall forming the fluid inlet passageway by a seal, and a fluid passageway extending through the adaptor and in communication with the fluid inlet passageway of the cylinder; and a fastener mounted in the fastener receiving passageway and in engagement with the third portion of the adaptor, the seal being distal to the fastener, wherein the the fluid passageway of the adaptor has a first part and a second part, the first part has a first end and does extend along a centerline of the adaptor, characterized in that the first end is within a second reduced diameter wall section of the first portion which is a fluid channel mounting portion, and spaced from the proximal end of the adaptor, that the the fluid passageway of the adaptor extends through the second portion and through the third portion, that the the fluid passageway of the adaptor terminates at a second end which is at a second end of the adaptor and that the second part is in fluid communication with the first part proximate to the first end. a cylinder having a body with a wall forming a fluid inlet passageway and a wall forming at least one fastener receiving passageway, the fastener receiving passageway being in communication with the fluid inlet passageway; an adaptor comprising a wall having a proximal end and a distal end, the wall including a first portion adapted to mount to an associated source of a fluid medium and extending from the proximal end, a second portion adapted to be engaged with an associated tool which can apply a torque to the adaptor, the second portion extending from the first portion, a third portion extending from the second portion, the third portion seated within the fluid inlet passageway of the cylinder and sealed to the wall forming the fluid inlet passageway by a seal, and a fluid passageway extending through the adaptor and in communication with the fluid inlet passageway of the cylinder; and a fastener mounted in the fastener receiving passageway and in engagement with the third portion of the adaptor, the seal being distal to the fastener, wherein the the fluid passageway of the adaptor has a first part and a second part, the first part has a first end and does extend along a centerline of the adaptor, characterized in that the first end is within a second reduced diameter wall section of the first portion which is a fluid channel mounting portion, and spaced from the proximal end of the adaptor, that the the fluid passageway of the adaptor extends through the second portion and through the third portion, that the the fluid passageway of the adaptor terminates at a second end which is at a second end of the adaptor and that the second part is in fluid communication with the first part proximate to the first end.