This is a review for the K&F Concept Lens Protection Set, sold on Amazon with the description:
K&F Concept Lens Case, 4 Sizes, Protective Bag for DSLR Cameras, Dark Gray, Dark Gray, Simplicity.

These are four protective cases for photographic lenses with a beautiful design (textured with pairs of inverted triangles forming a rhombus mosaic pattern). Each case is smaller than the one before it (I mention this because they are packaged one inside the other like a wooden Russian doll box). They offer good padded protection against minor bumps and dust and inclement weather. The exterior is dark gray, and the inner flap closure increases the size by about 4 centimeters, allowing you to tighten/close the bag inwards from the top using a drawstring (the end of which is sewn somewhat haphazardly, but since the stitching is on the inside of the hem, it's not noticeable if the drawstring is properly positioned) and a spring-loaded push-button fastener.

The sizes range from 7 cm in outer base diameter for the smallest, 8 cm for the second smallest, 9 cm for the medium-large, and 10 cm for the largest, with the black protective cover reaching 18 cm in height and the light gray top extension reaching 22 cm in height if not tightly closed.

The problem I've encountered is that, proportionally to the height of each lens model I usually use, both Nikon and Canon, the diameters of the bags aren't suitable for also storing the lens hood that most lenses include as standard in these cases (I'm referring to full-frame lenses equivalent to 35mm), whether they're Canon EF L series (for more professional or serious amateur use) or Nikon FX series high-end lenses, especially with wide-angle lenses. This is because the lens hoods are wider than the lens itself and sometimes significantly increase the diameter above the lens's filter/hood holder. So the lens fits perfectly in terms of height, with some bag even to spare, but the lens hood, with its diameter, is impossible to insert or remove. With some telephoto lenses or APS-C lenses, or lenses with low apertures (lower mid-range formats), the size of the lenses themselves and the lens hoods is much narrower in diameter (since their primary elements are smaller). These lenses can easily fit into bags of the appropriate size with the lens hood reversed or placed over the lens.
I am also familiar with and have reviewed other protective lens cases from the same brand, K&F, which are sold in sizes (S/M/L). These offer more padding and protection (and are also more expensive) and have a fairly similar interior diameter, with the XL size being slightly larger. Furthermore, some sizes (M/L/XL) include a blower for sensors or lenses and a shoulder strap attached to the case itself (so they don't require attaching them to another bag or belt with a plastic carabiner or rear strap). I'm referring to this format in case you want to take a look before deciding whether to complement the set or choose the other model of lens cases available from K&F Concept:

https://www.amazon.es/gp/product/B0DHRVB1L2/

Based on what I've already mentioned in this review, and because I think the quality of the materials and construction relative to the price and quantity (4 units of different sizes) is also good, if they fit the dimensions of your lenses, it's a great purchase option. My rating for this set of lens cases is:

""5 STARS "" [ * * * * * ] .