"I am Swedish and purchased a Batt-Latch 12 years ago. I originally used it to release a laminictic horse onto grass pasture late at night/early in the morning, and then when I woke up I put her back on the dirt paddock. The BL worked wonders and the horse rapidly learned when it was time to get onto the grass, and waited at the gate, then to step backwards when the alarm sounded and then hapilly trotted out in the other field.
Then I used it to feed the horses their lunch hay when my workhours changed. At lunchtime the BL released the gate onto a smaller paddock were I had put out the hay. I have also used it in a similar manner. I had two horses with very different nutritional needs, one was a very easy keeper and the other a hard keeper. In the morning they very let out in separate fields. The easy keeper got a limited amount of hay for breakfast, and the hard keeper was given ad-lib hay in his field. At lunchtime the BL released the gate between the fields, and the easy keeper then had its lunch served from the leftovers from the hard keeper. And they both had hay to keep them occupied until late afternoon. At the evening when I got home from work I served the evening hay.
Now I have added another use of the Batt-Latch. A pretty different one. I have two ponies, both are easy keeper and both are prone to laminitis. So they are on a very restricted diet. They eat pretty fast, and the problem is at night. The evening meal at 10 pm is finished at midnight, and then it is six hours until the morning feed at 6 am. Too many hours without feed.
So, after some thinking, I built at system with ropes and hinges (I think the english word is) and the battlatch. One Batt-Latch then holds two haynets - one in each stall - high up and without reach. At 2 am when I sleep tight in my bed, the BL releases the haynets, and they fall down so the horses can reach them. And they get a feed at night, and don't have to go no more than 4 hours between feeds even at night.
Here is a wrong-turned movie that shows one of the haynet fall down, the same thing happens simultaniously in the other stall.