[0.99 lb] I have the removable dew shield ES127ED APO model. I unthreaded the 3 barrel and used the Adapter 1 to thread the flattener/focal reducer directly to the focuser drawtube. I then threaded my SBIG ST2000xm to the front of the FR using the CCD camera adapter t-threads. The star field is tack sharp from edge-to-edge, no aberrations.

[8.7 oz / 249 g] The filter came boxed extremely well. I knew, right off the bat, the product was going to be great. Living in Eastern Idaho, one cannot be sure of the weather and cloud cover. I only had one chance to use it during our club's 5 star parties. 4 got rained out or cloud covered. The filter never got a good critique. I know it will be good and will send in a later review if I can get the scope to a dark site before the temp drops into the teens.

[1.25"] If you have a reflector or a refractor with a short focal length (under 1000mm), this is a very useful, high-quality Barlow - especially if you want to image planets with a CCD camera. My results have been great so far - much better than what I was able to do with a 2x. If you have a Schmidt- or Maksutov-Cassegrain, this is going to be overkill. I also wouldn't recommend it if you have a single-speed focuser; you really need to be able to fine-tune things to get this to work.

[3] This by far is the best focal extender in my collection. Flat from edge to edge with no image distortion. By far worth every penny. I will enjoy this extender for years..

[3] I use the 2 2X Explore Scientific Focal Extender with 2 Eyepieces in 25, 30, 35mm (70 degree FOV Bressers) primarily for viewing Deep Sky Objects: Clusters, Nebulas and Galaxies. My scope is a Meade LX 90 8 inch. The results with the 2 extender are pretty amazing. I begin by using a 20 or 25 mm eyepiece without the extender to find the object. Then for the increased magnification I switch to the 2 extender with either the 25 mm or 30 mm 2 eyepiece . Before getting the 2 extender I used a 1.25 2X extender (also Explore Scientific) with Plossls for viewing the deep sky objects. For the most part, with that setup the objects were bright and clear but, with the narrow FOV of the Plossls, not as dramatic. With the 2 extender and the 2 Bressers the clusters and nebulas are bigger, brighter, well defined objects. The clusters especially are bright and clear with many well defined points of light. The Galaxies are still fuzzy objects, but magnified. If there is a downside to the use of the 2 extender for me, it might be the weight. The combination of the 2 Extender, a 2 Diagonal, and a 2 eyepiece is heavy. But, so far, the scope performs just as it did with the 1.25 setup. Also, the 2 setup prevents the scope from going to zeinth. A 1.25 adapter is included with the extender so it is not necessary to have both the 1.25 and the 2 extenders. I am completely satisfied with the extender.

[1.25"] I've only run one night with this but from what I can see, there was no degradation of visual or photographic by putting this into the optical path, the build is rock solid.

[1.25"] I paid Only 99 dollars to get this FExtender w/4 optical elements, cause it was on discount!. Thanks B&H for that! Quality is superb and after a few weeks I am pleased with buying. I have improved my observation and photo/video capacity of my Comet Hunter. Great job of Exp. Scientific with this 2X extender. Highly recomendable.

[1.25"] I ordered this product to multiply magnifications of my eyepieces. I tested it for planets and double stars at very high magnifications, and really like the product. The green color coating looks great. I think $ is a bargain for a four element 3x barlow. B&H shipped really quickly. Overall, I like the B&H service and price, and I highly recommended this 3x barlow.

[3] I have used an xcel 3x Barlow for imaging solar system objects and also for visual observing, since about 5 years. Felt the need to try out a focal extender this time. This seems to be widely recommended and hence purchased this. I am quite happy with the results I am getting. The build quality seems to be great for this price point. Very happy with this!

[1.25"] A good nebulae filter