The 49mm, 720nm Infrared Lens Filter from Kolari Vision blocks visible light up to 720nm from the light spectrum. It features uncoated glass in an aluminum ring with 49mm threading on both sides.

Unlike the 550/590/665nm versions of this Kolari filter, this 720nm version does not require a full spectrum modification to be made to your camera, but only as long as you use the camera mounted on a tripod and set it to shoot long exposures. Otherwise, a full spectrum modification is required. That entails removing the camera's low-pass filter and replacing it with a clear filter. Once that's done, this 720nm filter will work as intended. (Kolari Vision can make the modification for you at a cost if you send in your camera to them.)