Lens for retrofitting a lighting system with LED lights

A lens comprising:

• an attachment portion including a first elongated aperture;
• and
• a light directing portion that is elongated along a direction that is non-parallel to the first elongated aperture;
• wherein the first elongated aperture is elongated along a vertical direction into the light directing portion, the light directing portion is elongated along a horizontal direction, the attachment portion includes a second elongated aperture that is elongated along the vertical direction into the light directing portion, and the second elongated aperture is spaced away from the first elongated aperture along the horizontal direction, the attachment portion includes a first protuberance that defines the first elongated aperture, and a second protuberance that defines a second elongated aperture, the attachment portion includes a wall that extends about the first elongated aperture, a first round aperture, and about the second elongated aperture, surrounding the first elongated aperture, the first round aperture, the second elongated aperture, and a second round aperture.