These are misdescribed; they produce poached, not boiled eggs. You have to break the egg into them and prick the yoke before microwaving.
The timings on the box don't seem to work, and after four attempts I've found it impossible to get the bottom of the egg cooked without over-doing the yolk. I'm afraid this is not the easy way to cook eggs for breakfast after all.
I purchased this item as my old microwave egg boiler had finally broken after about a year of use. As the version I had was unavailable, I purchased these as replacements. Although the price is more than reasonable, the quality of this product is extremely poor. They will cook the egg as promised in the microwave (poached consistency usually takes about 20-30 seconds in my microwave); however, because of their poor design, the lid will almost *always* blow off in the microwave while cooking. As opposed to my old egg boiler, in which the top screwed onto the base, with this model, you have to firmly push the top onto the base of the cup. It is almost impossible to do this securely, leading to these microwave explosions! I don't recommend these in the slightest, try to find models which feature screw tops or else you risk permanently decorating your microwave with bits of egg!
I bought these egg cookers thinking they would revolutionise my breakfast time! They don't. I must have wasted 12 eggs as each one exploded after a few seconds. I pricked the yolks as directed. I even drilled more holes in the covers, but it still happened. Not only that but the egg that is microwaved looks like rubber. Back to the old pan on the hob for a perfect taste. Don't buy.
These are OK, although you do have to experiment to find the perfect cooking style for your particular microwave. Several exploded eggs, followed by solid at the top with liquid underneath later, mine requires 1.5 minutes at 80% power then regular 10 second bursts until perfectly cooked. Just not sure it's worth the hassle, but they are handy if you can't find an egg cup.
These generally work well, but we have found you need more time than the instructions suggest - not sure if this is because the eggs have come out of the fridge. Occasionally the lid pops off, and the bottom part of the egg isn't fully cooked.
I can cook boiled eggs in no time and without having to remove the shell .... I think it's very useful even if it's often happened that the increase in pressure have blowed up the lid and I had to clean the eggs residues scattered in the microwave... I solved the problem placing the "Kitchen Craft Microwave Egg Boilers" inside another (no too big) container suitable for microwave which prevents the lid jumps away.