diff --git a/format/products-bitmask.js b/format/products-bitmask.js
index af2a6361..f28e5a9a 100644
--- a/format/products-bitmask.js
+++ b/format/products-bitmask.js
@@ -2,7 +2,7 @@
 
 const createFormatBitmask = (modes) => {
 	const formatBitmask = (products) => {
-		if(Object.keys(products).length === 0) return null
+		if(Object.keys(products).length === 0) throw new Error('products filter must not be empty')
 		let bitmask = 0
 		for (let product in products) {
 			if (products[product] === true) bitmask += modes[product].bitmask
diff --git a/index.js b/index.js
index b4c14de7..93409c1c 100644
--- a/index.js
+++ b/index.js
@@ -30,7 +30,7 @@ const createClient = (profile) => {
 				time: profile.formatTime(profile, opt.when),
 				stbLoc: profile.formatStation(station),
 				dirLoc: dir,
-				jnyFltrL: [products].filter(x => x !== null),
+				jnyFltrL: [products],
 				dur: opt.duration,
 				getPasslist: false
 			}
@@ -63,7 +63,7 @@ const createClient = (profile) => {
 
 		const filters = [
 			profile.formatProducts(opt.products || {})
-		].filter(x => x !== null)
+		]
 		if (
 			opt.accessibility &&
 			profile.filters &&
@@ -226,7 +226,7 @@ const createClient = (profile) => {
 				ageOfReport: true, // todo: what is this?
 				jnyFltrL: [
 					profile.formatProducts(opt.products || {})
-				].filter(x => x !== null),
+				],
 				trainPosMode: 'CALC' // todo: what is this? what about realtime?
 			}
 		})