It didn't make our list of the best car diffuser products, but this aromatherapy essential oil diffuser by TT-Star is still a good option if you're looking for a cheap essential oil car diffuser. Its car diffuser vent clip design means it doesn't take up any cup holder space, although it won't be as effective as the electronic models.\r\n\r\nWhy We Like It - TT-Star Aromatherapy Steel Car Diffuser\r\nThe TT-Star Aromatherapy Steel Car Diffuser is an aromatherapy essential oil car diffuser that is cheap, simple, & efficient. The TT Star car diffuser vent clip-on design means this essential oil diffuser won\u2019t take up any of your valuable cup holder space, and the stainless steel locket is sure to last for years to come.\r\n\r\nPerformance\r\nAlthough it won\u2019t compare to the performance of the InnoGear Essential Refresher Ultrasonic Aromatherapy Diffuser, the TT-Star essential oil car diffuser can still do pretty well for a manual model. The overall effectiveness will really depend on the strength of the essential oil you are using, and the airflow from the vents (hot air will be the most effective!). You can easily change the scent of this aromatherapy car diffuser by using different oils on different pads, and simply changing them out when you tire of the same old scent.\r\nDesign\r\nThis stainless steel vent clip essential oil diffuser has a very simple design that requires no electricity to freshen up your vehicle (the RoyAroma Aromatherapy Essential Stainless Freshener has a similar steel stainless design, but it comes with 12 pads instead of 10). Judging by the customer reviews, the best location for these little devices is in front of a vent that is blowing hot air, but since the car diffuser vent clips are covered with a black rubber coating, you won't have to worry about the metal scratching up your vents.\r\nValue\r\nBased on the product information available (mainly the stainless steel design and the 10 included felt pads), we feel confident in saying that you get your money's worth for this product. It only costs $7.99 and has free shipping & free delivery through Amazon Prime. It also scored a 4.2\/5 star rating, so customers generally seem to be happy with it. Alternatively, for about 2.5 times the price you can get the Gulaki Diffuser Essential Oils Multifunction, which functions as an aromatherapy essential oil car diffuser\/humidifier\/USB charger.\r\nTT-Star Aromatherapy Steel Car Diffuser Wrap Up\r\nThe TT-Star Aromatherapy Steel Car Diffuser is a solid choice if you're looking for a car diffuser that doesn't need electricity to operate, and won't take up any of your cup holder space. While, performance-wise, it can't compare to the electronic models, for what it is, it works well and even includes 10 replacement pads, so we would definitely recommend this product for your vehicle!