Grivel - Spider - Snow spikes tested

Used for dog walking on footpaths across fields during 'Beast from East' storm. Excellent grip where thin layer of snow hid icy patches - great for confidence. Spikes excellent quality but could have been longer - foot did slip forwards on ice when going down a relatively moderate gradient. Balls of icy snow did accumulate between the plate and hiking boots where snow wasn't completely frozen. Straps left a distinct abrasion strip on the heels of my Scarpa leather boots which wasn't expected, considering the straps felt loose and one kept slipping down. Getting very stiff heel arch plate in place and getting straps round heel tight enough was a nightmare. Found spike/chain mix (Pogu) easier to put on and use as they are not restricted to insole spikes.

I bought these on a whim because they had a great reduction in a climbing shop (not Alpine Trek). I've had them a few years but only used them occasionally. Why? Because they don't lock on to the boot well. Once the straps are on and as tight as you can get, it's almost impossible to keep the heel strap tight when locking the clip, because the clip doesn't hold the strap in place as you lock it, so they loosen slightly. Then when walking (downhill in particular) the spike plate moves around and slips towards your heel because the straps are not tight enough. This means the strap round the heel becomes even slacker and eventually the clip loosens, the strap slips out and you have to stop and re-fit them! Extremely annoying when you're trying to get down a cold, icy mountain. I'm not comparing these to crampons, but to my friend's micro spikes that just he slipped on and they stayed put.
However there are two plus points. 1 They're lightweight and 2 The spikes can be replaced if they break or become blunt. But that doesn't make up for the hassle of using them.