There's 4 contenders, 1 isn't made anymore. They all have a catch, but generally if you like an enhancer, one will be favoured. These are my opinions on them. 'Pigs ear' Soft, well fitting and accommodating, but can be a little floppy, no longer made. 'DG scope enhancer' A harder version of the pig's ear, but it's stiffness can be problematic across the 3 positions used in FT, because it can sometime be hard to accommodate the different head positions with it. 'Bisley scope enhancer' Accommodates a wide range of head positions, but it's fit isn't perfect. There's light leak on the outside edge, and the inside edge can touch the nose. 'Concertina type' Soft, accomodates a lot of positions without being floppy... not something to rely on for correct head position, because it moves up and down a lot. I use the Bisley ones. If you find the enhancers are too loose on the scope, then you can use a cable tie or two to tighten it down. Use something like washing up liquid to ease them on and a soak in hot water, or a pass with a hair dryer helps soften them.