Urbatterier

• Apeks: SR927W or equivalent (had an SR820SW inside). Renata 395.
• Marathon navigator: Replacement battery is either the low drain 395/SR927SW/V395/SR57 cell or the high drain 399/SR927W/V399/SR57 cell, the high drain cell is supposed to last longer. Both are Silver Oxide 1.55V 9.5x2.6mm cells.
• Regent: 396(high drain)/397(low drain) --395/SR927SW fits better (larger)
• Timex Q + Sekonda: sr626sw (377)

Low drain/high drain

The difference is marginal, as both use the same chemical system. But some 
parameters can be optimized either for low internal resistance (high drain) or 
low self discarge and longer shelf life (low drain).

http://forums.watchuseek.com/f6/batteries-low-vs-high-drain-422356.html