Air injectors are the necessary pool parts that help distribute air from a spa's blower line in order to deliver the spa's relaxing soft massaging feature. These are also the contraptions responsible for delivering pleasant therapeutic air bubbles that many consumers want from their spas.

One of the best air injectors you can get in this category is the O-Ring Jacuzzi/Sundance Ultem Air Injector made for Sundance Spas (Models: 90-423-5313 | SD6540-228 | 6540-228 | 313 ). It has 1.05 x 1 x 0.2 inches as its dimensions and weight of about 1.6 ounces, making some of the most compact size spa parts sold by the Sundance Spas brand.