I was undecided whether to buy the Dew Shield but the addition of a mirror to the Telrad seemed a good idea. Installation is easy with just 2 screws to remove, position the shield brackets over the holes, and then replace the screws making sure not to over tighten and strip out the threads in the plastic case.
In operation the dew shield did not prevent dew forming, but it did seem to delay it. For me the star of the show was the mirror. That flips into place when you need it, and gives a much more comfortable viewing angle with elevated telescope positions.

i have always had a telrad finder on my telescopes and find them invaluable for alignment with go to systems; i bought the dew shield with mirror to use in the situation when the telescope is at a steep angle thus making it difficult to sight without getting in a verry uncomfortable position. The mirror solves this problem like a diagonal thus making it much easier too align.

I had some issues mounting this on my TelRad. I am not sure if my TelRad is just rather wide but it is difficult to get the cover to mount properly because of the washers that protrude too much . If you can get it to mount then then the
plates bend out some. Once mounted it seems OK. Not had a chance to test its dew ability yet though.

Unfortunately I’ve found this doesn’t work very well. It doesn’t prevent dew from forming, though it does slow up the formation very slightly. It also works better if you take the mirror out which is disappointing. I’ve only used it a few times but I wouldn’t purchase it again.

The mirror gives just enough field of view to see stars that are outside the outer circle and gives a comfortable viewing position. I will be upgrading my other Telrads with this device

I bought the mirror version for my Dob. Every time that you move it, the screws come loose and being plastic you cannot tighten them much and it flops over. Being small and black bit difficult to do in the dark. Tried to tighten them and the housing split. However, superglue to the rescue. I modified the screws by making them thumbscrews using scrap plastic. All said, it does do the job.

Same as the Tetrad Finder the dew shield is AOK.brilliant delivery and service 10 out of 10 for me.Thankyou.