Originally Posted by Tog Tan

Yo Frank, your pix looks like one of the varieties of the Kluay Nam Wah as the peel is a little glaucous and the tip of the fruit if more 'beaked' than the Kluay Kai. Also, the Klauy Nam Wah fruits are slightly angular. The Kluay Nam Wah has more distinct varieties than the Klauy Kai. These two cultivars make up the bulk of the 'naners consumed in Thailand.

As you can see from the pix below of the M'sian Pisang Mas which is an identical twin to the Kluay Kai, the fruits has a smooth peel and the tip is blunt. So far from the Kasaesart Research Station in Bkk, they list the following varieties besides the nominal Kluay Kai;
1. Kluay Kai Bo Lah
2. Klauy Kai Lek Yak Soh Thon
3. Kluay Kai Thong Ngaey
4. Kluay Kai Pratabong
5. Kluay Kai Thong Ruang
Their difference is in their form and taste.

Pix of Pisang Mas, the M'sian version of the Kluay Kai. As you can see the fruits are short, plump and egg like, hence the Thai name. In the background is the Pisang Raja Udang aka Cuban Red for size comparison.