Most of the bird's eye cili (Capsicum frutescens) you get in the supermarket in Malaysia are from Thailand, the dark green, slim and rather long ones. Whilst they are hot, the heat isn't that intense and is considered to be on the lowest rung for bird's eye chilli varieties. There is another variety that is also common locally, and spicier than the Thai version - this is the Cili api Centil. It is also marketed as Cili padi Kampung.
The fruit of Centil is usually 1 - 1.5 inches long, but can go up to 1.8 inches long and they are about 0.5 inches wide at the base and tapers to a point. This gives the chilli a pyramidal bullet-shaped appearance. The unripe fruit are a light, shiny green and matures to a slightly darker green before turning brownish (red plus green) and then to a bright red colour when fully ripened. They are supposedly a productive variety but susceptible to leaf curl disease caused by viruses.