Per me è il nome dell'organizzazione/ente che effettua i controlli... Non so se c'entri col tuo testo, ma ho trovato anche "GS Mark":
The GS Mark is recognized throughout Germany and EU countries as symbol of safety. German consumers are willing to pay a higher price for products if there is a strong certification mark on it. The GS Mark minimizes manufacturers' risk of product liability and provides manufacturers with the confidence that their products are safe, legal and of high quality. The GS mark also assures end users that the product has been independently tested by an authorized third party (Intertek) for safety.

A GS mark issued by Intertek will carry its "GS Mark" identifier above the mark. Moreover, Intertek can provide concurrent testing and certification for GS Mark, S Mark, CE Mark and CB Certificates for the European Market, saving you significant time and money.

Any product bearing the GS Mark indicates that it was tested and complies with the minimum requirements of the German Product Safety Act (a.k.a. ProdSG). The GS Mark, which stands for “Geprüfte Sicherheit” in German and means Safety Tested, is a licensed mark of the German government and may only be issued by an accredited product safety testing and certification agency.

Advantages of the GS Mark include:

•Recognized by consumers throughout Germany and EU countries as a symbol of safety and quality
•Provides a marketing advantage by creating consumer trust, confidence, and purchasing motivation
•Minimizes manufacturers' risk of product liability
•Provides manufacturers with the confidence that their products are safe, legal, and of high quality
•Emphasizes your company's commitment to safety and quality
•Assures end users that your product has been independently tested by an authorized third party for safety
•Exceeds required legal standards in many cases
•More highly regarded than the CE Mark since it is verified by a third party testing and certification organization
Examples of products the GS mark can be found on:

•Air-Cleaners
•CD players
•Home A/V Equipment
•Coffee Mills & Grinders
•Commercial Deep Fryers
•Household Appliances
•Lab/Measurement Equipment
•Luminaires
•Office/IT Equipment
•Power Tools
•Pumps for Liquids
•Range Hoods
•Sports Equipment
•Office Furniture
•Toys
http://www.intertek.com/marks/gs/

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Note added at 13 mins (2012-01-27 14:06:07 GMT)
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Il 90 % degli acquirenti di apparecchi e macchinari Hi-Tech, trattandosi di prodotti dall’elevata complessità, vorrebbe un controllo sui messaggi pubblicitari dei produttori da parte di esperti indipendenti e disinteressati. Il prestigioso marchio GS/TÜV offre quindi un importante contributo per la decisione d’acquisto. Un produttore certificato deve essere in grado di commercializzare beni di invariata qualità e sicurezza. Rowa ha ottenuto il marchio GS come unico fornitore nel mercato di magazzini automatici.
[...]
È stata provata la sicurezza del sistema, che soddisfa i requisiti necessari per poter ricevere un marchio GS”.



Il marchio GS garantisce la qualità di un prodotto. Nel processo di assegnazione del marchio GS ci si attiene alla legislazione sulla sicurezza delle apparecchiature, considerando anche tutte le altre direttive e disposizioni di legge specifiche. Inoltre TÜV Rheinland controlla i centri di produzione. “Conferiamo il marchio GS solo quando il prodotto supera le diverse prove.[...]"
http://www.rowa-italia.it/Comunicato-stampa-9-TUEV.643.0.htm...

Inoltre la qualità dei processi di produzione viene esaminata e confermata attraverso controlli effettuati regolarmente da Istituti di Controllo, i quali autorizzano il marchio di sicurezza GS.
http://www.rems.de/rems-made-in-germany_7002_3.aspx