Types of HDB

With technology being so advanced, so is the type of HDB (Housing Development Board)flats. 10 years ago we never used classification like these ever before and now kind of lost. So I thought I can find the "classification" through the HDB site but to my very surprise, it does not have it.

After searching over sites after sites that gives me rubbish information, I finally found this. So hope it helps those who are also stumble on this information.
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Did you know that there are different HDB flat types? And within each flat type, there are varying models:
2 bedroom flatConsists of 1 bedroom, kitchen, living room:
2 ‘I’ (Improved) 45 sqm/484sqft2 ‘S’ (Standard) 41 sqm/441sqft (floor plans: 1)
3 bedroom flatConsists of 2 bedrooms, kitchen, living room:
3 ‘A’ (Modified) 90sqm/969sqft3 ‘NG’ (Modified) 83sqm/896sqft3 ‘A’ 75sqm/807sqft3 ‘NG’ (New Generation) 69sqm/743sqft (floor plans: 1)(2 toilets, master bedroom with attached bathroom)3 ‘I’ (Modified) 70sqm/750sqft3 ‘S’ (Simplified) 65sqm/700sqft3 ‘I’ (Improved) 60sqm/646sqft(No attached bath, toilet and bath separated, no storeroom)3 ‘STD’ (Standard) 54sqm/581sqft (No attached bathroom/storeroom. Upgraded units have extra utility room or toilet)
4 bedroom flatConsists of 3 bedrooms, kitchen, living room.
4 ‘A’ 105sqm/1130sqft(2 bathrooms, master bedroom with attached toilet, storeroom)4 ‘NG’ (New Generation) 92sqm/990sqft (floor plans: 1)
4 ‘S’ (Simplified) 85sqm/914sqft (floor plans: 1)(2 bathrooms, master bedroom with attached toilet, storeroom)4 ‘I’ (Improved) 83sqm/893sqft (toilet and bath separated, no storeroom)4 ‘STD’ (Standard) 73sqm/786sqft
5 bedroom flatConsists of 3 bedrooms, kitchen, dining room, living room, storeroom.Master bedroom comes with attached bathroom.

5 ‘A’ 135sqm/1453sqft5 ‘I’ 123sqm/1313 sqft (floor plans: 1, 2, 3, 4, 5)5 ‘S’ 121sqm/1300sqft (floor plans: 1)
Executive flat
EA (Exec Apartment) 141sqm/1518sqft (single storey) (floor plans: 1)EM (Exec Maisonette) 145sqm/1560sqft (double storey) (floor plans: 1)(double story, 3 bedroom/bath upstairs, balcony+additional room)MG (Multi-Generation) 165sqm/1776sqft

Read exact place here