The ZII and nummer 5 are Dutch marks. ZII limited assay mark zilver 835/000 minimum.
The mark with the number 5 is a weight indication mark. These weight indication marks consist of a series of 20, with the numbers 1 to 20, multiply the number by five to obtain the gross weight in grams, in this case the weight; 5x5 = 25 gram. These marks give no guarantee by themselves but must always occur in combination with hallmarks or duty marks.
For Dutch marks see: viewtopic.php?f=5&t=32028