http://www.niteyelight.com/article/?type=detail&id=25

TF40
1. Light source: 1xCree XM-L U2 LED
2. Battery: 4xCR123 0r 2*18650
3. Output & Runtime:2-520LM/2-100Hours
4. Output regulation: magnetic ring infinitely variable dimming switch and tail cap switch
5. Circuit design: constant current circuit, constant brightness.
6. Working voltage:6-12V
7. Waterproof to IPX-8
8. Material: stainless steel and aerospace aluminum
9 Dimension: 220 mm(L) X 49 mm(D)
10. Weight: 212 gram

TF25
1. Light source: 1xCree XM-L U2 LED
2. Battery: 2xCR123 0r 1*18650
3. Output & Runtime:2-500LM/1-50Hours
4. Output regulation: magnetic ring infinitely variable dimming switch and tail cap switch
5. Circuit design: constant current circuit, constant brightness.
6. Working voltage:3-6V
7. Waterproof to IPX-8
8. Material: stainless steel and aerospace aluminum
9 Dimension: 154 mm(L) X 49 mm(D)
10. Weight: 185 gram

TF20
1. Light source: 1xCree XM-L U2 LED
2. Battery: 2xCR123 0r 1*18650
3. Output & Runtime:2-480LM/1-60Hours
4. Output regulation: magnetic ring infinitely variable dimming switch and tail cap switch
5. Circuit design: constant current circuit, constant brightness.
6. Working voltage:3-6V
7. Waterproof to IPX-8
8. Material: stainless steel and aerospace aluminum
9 Dimension: 142 mm(L) X 33 mm(D)
10. Weight: 132 gram