The phrase "are only designed for" is correct and usable in written English.
It can be used to specify the intended purpose or function of something, indicating exclusivity in its design.
Example: "These tools are only designed for professional use, not for casual consumers."
Alternatives: "are solely intended for" or "are exclusively made for".
Preventative treatments are only designed for oaks.
Hand-held thermal cameras, however, are only designed for measuring surface temperatures.
But the tires on most Ford light trucks -- sport utilities and pickups -- are only designed for a temporary top speed of 106 to 112 miles an hour.
Then, the additional monitors are only designed for elementary siphons, whose control depth variables can be obtained by solving a linear programming problem.
However, shear connections are only designed for gravity loads that produce shear, and there is a lack of knowledge in their behavior at elevated temperatures.
But the problem is, that the common clustering methods (like the fuzzy c-means method) are only designed for treating crisp data, that means they provide a fuzzy partition only for crisp data (e.g. exact measurement data).
This decorator is only designed for routines that work with a single window.
It has 35,000 registered users, and while he is eager to expand that pool, right now it is only designed for use in the Washington and Baltimore regions.
In a conventional coal-fired power plant, which is only designed for electricity generation, 2/3 of fuel energy is wasted through stack gases and cooling water of condensers.
Furthermore, flight and freestream conditions may change considerably during an aircraft mission while the aircraft itself is only designed for multiple but fixed design points thus impairing overall performance.
The first VCS proposed by Naor and Shamir was only designed for encrypting a black-and-white secret image; subsequently, some colored VCSs (CVCSs) for sharing colored images were proposed to enhance the applicability.
