Everyone I have spoken too says the Triumph ones are very overpriced and known to fail regularly. I got an Oxford 'Hot Grips' one for 1' cruisers - works brilliantly. You use the provided grips but you can trim the ends and fit end weights or mirrors etc.
https://www.google.com.au/search?q=Oxford+Hot+grips+Cruiser+1"&rlz=1C1CHZL_enAU721AU722&source=lnt&tbs=ctr:countryAU&cr=countryAU&sa=X&ved=0ahUKEwjUgf6EiLHWAhXFNpQKHbqDA_QQpwUIHg&biw=1098&bih=488
I got mine from Poland on eBay where they are about $50 less than here in Oz with free international postage but when I last checked the Cruiser 1" models were gone from the site I purchased from. I thi9nk they were US$80 delivered. i did notice that other Polish sites offer Oxford gear the cheapest. Must be made there and production staff pinch them to re-sell - who knows.
Just for you also found a place with cheap replacement side panel badges.
Triumph Rocket III Classic Roadster Touring side panel plate Aluminium 40401 M | eBay
as well as my favourite
Triumph Rocket III Classic Roadster Touring side panel plate Aluminium 40409 | eBay