Nellie,

I've just wi-fried myself in the interests of research and providing answers to some of your questions.  I measured the radiation coming off my ipod touch and my ipad pro.  I put each device inside a faraday cage so that I could eliminate other sources of RF.  

Measurement one: faraday cage closed, device has wi-fi turned on but is not connected to router. Ipod: 5 mw/m2; ipad 17 mw/m2.

Measurement two: open one side of faraday cage so router signal can reach device.  Get device to connect to wi-fi network. Ipod: 15 mw/m2; ipad: 27 mw/m2.

Measurement three: turn off router but leave faraday cage open.  Ipod: no increase in RF; ipad: 34 mw/m2.  Why the ipad increased its RF when I turned off the router, I do not know.  Perhaps it was freaking out that the signal had been lost and was upping the ante, looking for a new signal.

It would seem that the larger the device, the more RF it emits.  It might have been when I was shopping for the ipad that I measured the RF in the shop, but I vaguely recall having seen much higher levels of RF than this.

I believe laptops emit much less RF, perhaps only half or less, and that older laptops emit less RF.  Others might have more info on this than I can provide.

Given my experience with Apple products and given news stories about Samsung, I doubt that either of these companies cares about your health.

One thing you need to be careful of when enclosing your device in a sleeve is that if the device is struggling to connect because of the sleeve, it will emit more RF while trying to find a signal.  So what have you achieved?  And if the device can still make the connection despite the sleeve, then just how effective is that sleeve?  Also, why would you want to reduce the effectiveness of the network connection by using a sleeve?  You might suffer constant drop-outs.

Regarding mobile phone chips, the circle of EMR combatants that I move in, takes a dim view to gimmicks.  I'm not saying for sure that they don't work, just buyer beware.  One chip I looked at a while ago said that it directs the RF out one side of the phone.  So you stick the chip on the rear of the phone, remember to put the phone in your pocket with the front facing away from your body, and bingo, you irradiate every one coming near you.  Sure hope you're not sitting next to me on the train.

I also looked at a phone sleeve that had two pockets to it.  When you want to be able to receive phone calls, you place the phone in the smaller pocket which is open at the top so the internal antenna can connect to a phone mast.  When you want total protection, you put the phone in the larger pocket so that it is fully enclosed.  As with the tablet sleeve, are you improving, or making the situation worse?  And if you can actually receive a phone call while the phone is in the larger pocket, then you're probably irradiating yourself even more.  You could make something like this yourself out of a good quality shielding fabric if you have some sewing skills.  I considered doing this with scraps of left-over shielding fabric and selling them as a fund-raiser for my organisation.

Since I don't use a mobile phone I cannot say for sure how spot on my views are and neither can I take measurements for you.  But no-one in my circle of EMR antagonists has bought any of these products, that I am aware of.