Choosing a ceiling diffuser for ventilation ducting air distribution usually comes down to three questions: what duct size you are connecting, how large a ceiling opening you need to cover, and how many diffusers you need at once. The four options here show that range clearly: a two-pack of 24-inch Titus lay-in panels with a 12-inch round neck at the top of the listed prices, a single 24-inch Titus with a 10-inch round neck in the middle, a 6-inch round steel Selkirk just below it, and a two-part RHEIA assembly at the lowest listed price.
Quick take
The Titus TMS3W 12R pack of 2 is the only listing that includes two 24-inch square ceiling diffusers with a 12-inch round neck. The Titus TMS 24x24 with a 10-inch round neck is the single-unit version of the same TMS series. The Selkirk 01790006CW is a compact 6-inch round steel diffuser. The RHEIA 10-04-260 is the lowest priced option and is a two-part aluminum assembly for 360-degree air distribution.
Listed-price comparison
The listed prices run from USD 25.31 to USD 90.00, a spread of USD 64.69 across the four products.
| Product | Listed price | Price bar |
|---|---|---|
| Titus TMS3W 12R Square Ceiling Supply Diffuser 24 x 24 in 12 in Duct Pack of 2 | USD 90.00 | |
| Titus TMS 24x24 Ceiling Diffuser 10" Round Neck Square Air Supply Grille White | USD 45.00 | |
| Selkirk 01790006CW Ceiling Diffuser 6" Round Steel 360 Air Distribution | USD 40.60 | |
| RHEIA 10-04-260 Ceiling Diffuser 360 Air Distribution Assembly | USD 25.31 |
Decision matrix
| Diffuser | Duct connection | Face / count | Standout listing detail | Listed price |
|---|---|---|---|---|
| Titus TMS3W 12R | 12 in round | 24 x 24 in, pack of 2 | TMS-series steel, white powder coat | USD 90.00 |
| Titus TMS 10" | 10 in round | 24 x 24 in, single | TMS-series steel, white powder coat | USD 45.00 |
| Selkirk 01790006CW | 6 in round | Round step-down, single | Steel, bright white finish | USD 40.60 |
| RHEIA 10-04-260 | Standard duct sizes 6-12 in | Two-part assembly | Aluminum, white powder coat, adjustable air pattern | USD 25.31 |
Product notes
Titus TMS3W 12R Square Ceiling Supply Diffuser 24 x 24 in 12 in Duct Pack of 2
If you need two matching 24-inch ceiling diffusers for one project, this Titus pack bundles both panels with a 12-inch round neck, heavy-gauge stamped steel, and a factory white powder coat. It also provides 360-degree air distribution. The limiting side is the listed price: it is the highest in this set. It is also listed as New - Open box, so the product photos are part of what you are buying.
Titus TMS 24x24 Ceiling Diffuser 10" Round Neck Square Air Supply Grille White
The Titus TMS 24x24 with a 10-inch round neck uses the same TMS-series steel construction and white powder coat, but comes as a single diffuser. It costs less than the two-pack and can be a better fit when you only need one 24-inch panel. The trade-off is count: you receive one unit, so a multi-diffuser layout requires purchasing more than one listing.
RHEIA 10-04-260 Ceiling Diffuser 360 Air Distribution Assembly
The RHEIA 10-04-260 is the least expensive option here. It is a two-part assembly that distributes air in 360 degrees, with an aluminum body, a white powder coat, and a horizontal or vertical adjustable air pattern. It is compatible with 5/8-inch or 1/2-inch drywall, making it useful for drywall ceiling work. The limitation is that it is not a fixed 24-inch lay-in panel; it is built for standard duct sizes from 6 to 12 inches, so it takes a different fit approach from the round-neck Titus and Selkirk units.
Selkirk 01790006CW Ceiling Diffuser 6" Round Steel 360 Air Distribution
The Selkirk 01790006CW is a round step-down diffuser built from steel with a bright white finish and a 6-inch size. That makes it a direct match when your duct connection is 6 inches and you want a compact circular unit. Its listed price sits between the RHEIA and the Titus single. The limitation is the smaller face compared with the 24-inch Titus panels, so it is not aimed at large lay-in ceiling grid openings.
Final recommendation by use case
For a two-grille, 24-inch lay-in installation with a 12-inch duct connection, the Titus TMS3W 12R pack of 2 gives you both panels at one listed price. For a single 24-inch panel with a 10-inch duct connection, the Titus TMS 10-inch round neck version is the matching choice. For a 6-inch round steel diffuser, the Selkirk 01790006CW is the most direct fit. For the lowest listed price and a two-part diffuser for drywall, the RHEIA 10-04-260 covers that use case.
