diff --git a/inema/inema.py b/inema/inema.py
index 4b96725..8eb332e 100644
--- a/inema/inema.py
+++ b/inema/inema.py
@@ -25,16 +25,16 @@ _logger = logging.getLogger(__name__)
 # This allows to ship multiple products.json files for announced future price/product
 # changes.
 def load_products():
-    global marke_products
     ps = [ e for e in resource_listdir(__name__, 'data')
             if e.startswith('products-') and e.endswith('.json')
             and e <= 'products-{}.json'.format(date.today().isoformat()) ]
     ps.sort()
     ps.insert(0, 'products.json')
     products_json = resource_stream(__name__, 'data/' + ps[-1]).read().decode("utf-8")
-    marke_products = json.loads(products_json)
+    products = json.loads(products_json)
+    return products
 
-load_products()
+default_products = load_products()
 
 formats_json = resource_stream(__name__, "data/formats.json").read().decode("utf-8")
 formats = json.loads(formats_json)
@@ -94,16 +94,21 @@ class Internetmarke(object):
         return [p, t, k, s]
 
     def get_product_price_by_id(self, ext_prod_id):
-        price_str = marke_products[str(ext_prod_id)]['cost_price']
+        price_str = self.products[str(ext_prod_id)]['cost_price']
         return int(decimal.Decimal(price_str) * 100)
 
-    def __init__(self, partner_id, key, key_phase="1"):
+    def __init__(self, partner_id, key, key_phase="1", products=None):
         self.client = Client(self.wsdl_url)
         self.partner_id = partner_id
         self.key_phase = key_phase
         self.key = key
         self.soapheader = self.gen_1c4a_hdr(self.partner_id, self.key_phase, self.key)
         self.positions = []
+        if products is None:
+            self.products = default_products
+        else:
+            self.products = products
+
 
     def authenticate(self, username, password):
         s = self.client.service